Weather Extremes

Hottest air temperatures reported on Earth

By: weatherhistorian, 5:20 PM GMT on October 22, 2010

In my previous post, I questioned the validity of the hottest temperature measured on earth: the 58°C (136.4°F) reading from Al Azizia, Libya in September 1922. If, in fact, this record is not valid, then what might be the absolute maximum temperature measured on earth? There are just a handful of regions in the world that have the potential of recording temperatures of 130°F (54.5°C) or more (excluding heat burst measurements). I list them here in no particular order:

1) Death Valley, California (see list below) and the Colorado Desert in the southern part of the state (where anecdotal temperatures as high as 130°F have been reported and temperatures as hot as 126°F (52.2°C) officially measured (at Thermal on July 28, 1995 and Mecca on June 26, 1990). Also, the Colorado River Valley from the southern tip of Nevada to the Gulf of California can be as hot or even hotter, with an official reading of 128°F (53.3°C) measured at Lake Havasu City, Arizona on June 29, 1994.

2) Possibly some portions of the western Sahara Desert, specifically the Tidikelt Depression in Algeria, and lowest areas of northern Mali and northeastern Mauritania. Unfortunately, there are no weather stations in these areas, the nearest being In Salah, Algeria and Araouane in Mali (see below).


Figure 1. The World Survey of Climatology, Vol. 10: Climates of Africa reproduced this map of possible absolute extreme maximum temperatures, but it is based upon the dubious maximums recorded during the colonial era, and, in fact, no temperature above 124°F (52°C) has ever been recorded in the Sahara Desert in modern records.

3) The interior of southeastern Saudi Arabia in portions of the Rub Al Khali Desert and areas around the Persian Gulf. Again, unfortunately, there is no climate data from the Rub Al Khali Desert and it is simple speculation, given the topography and characteristics of the region, that temperatures as high as 55°C might be possible. The populated areas along and just inland along the shores of the Persian Gulf have measured official temperatures as high as 127°F (52.6°C) at Abdaly, Kuwait, and 126.5°F (52.5°C) at Hamidiyeh, Iran. Unofficial temperatures of 129°F (53.9°C) have been reported from this region as well.

4) The region along the lower Indus River of Pakistan centered around Jacobabad. Temperatures as high as 128.3°F (53.5°C) have been measured here (Moen-jo-Daro on May 26, 2010) and 125° is reached almost every year during May in Jacobabad. We can speculate that at some point 130°F may be possible.

5) Other regions of potential (and recorded) extreme heat include the eastern part of the Dasht E Lut Desert in Iran (no records), the Dead Sea area of Israel, Palestine, and Jordan (where temperatures up to 126°F/52°C) have been recorded), and the central-western inland coastal region of Saudi Arabia (around Jeddah) where 126°F (52°C) has also been measured.

Studies by geographer Mark Jefferson (1926) and by Hoffman (1963) conclude that the highest possible surface air temperature on earth (measured by standard modern instruments) would be in the range of 131-133°F (see Weather and Climate Extremes by Dr. Paul F. Krause and Kathleen L. Flood, U.S. Army Corps of Engineers Topographic Engineering Center paper TEC-0099, September 1997.

So below is a list of all both 'measured' and 'anecdotal' absolute maximum temperatures on record above 129°F (54°C). The lists are not completely comprehensive so far as many European colonial measurements made in Africa prior to 1950 in places like Tunisia, Algeria, Libya, and Mali. Multiple readings of 54°-55°C were reported in these countries between 1900-1940.

VALIDITY SCORE: I have rated all the below records on a score from 0-10: (0) Zero means completely unbelievable to (10), indisputable.

136.4° (58.0°C) Sept. 13, 1922 Al Azizia, Libya
SOURCE: R. Ufficio Centrale di Meteorologia e Geodinamica; Osservazioni dell anno 1922 Rome, Italy
NOTE: This site reported numerous 130°+ reading between 1920-1926.
NOTES: See detailed discussion of this event in my previous post.
VALIDITY SCORE: 1
The evidence appears to be overwhelmingly against the validity of this measurement.

134.8° (57.1°C) July 12, 1936 Tindouf, Algeria
SOURCE unknown, perhaps Service Meteorologique, Dakar
NOTES: The hottest temperature measured at Tindouf in modern records is 118° (47.8°C) in July 1998. The older records (1925-1950) as reported in Tables of Temperature, Relative Humidity and Precipitation for the World, British Meteorological Office, 1967 show an absolute maximum of 122°F for Tindouf. A reading of 57.1°C was also reported from Ouargla, Algeria on Aug. 27, 1884.
VALIDITY SCORE: 0
There is no way this site could have recorded such a temperature given its altitude near 2000..

134° (56.7°) July 10, 1913 Greenland Ranch, Death Valley, California, USA
SOURCE Monthly Weather Review, June 1915, U.S. Dept. Of Agriculture
NOTES: This site reported several other 130°F+ readings during this heat episode (130° on the 12th and 131° on the 13th) but never again after this July of 1913. Many in depth articles have been written about the validity of the measurement. See:

Monthly Weather Review, June 1915 pp. 278-280

The Climate of Death Valley, by Steven Roof and Charlie Callagan, Bulletin of the American Meteorological Society, December 2003.

Weatherwise magazine, Retrospect: July 10, 1913: Highest Temperature Ever Recorded in North America, by Sean Potter, July-August 2010 issue.

Weatherwise magazine, 134°, by David Ludlum, June 1963 pp. 116-117

The record has been scrutinized perhaps more than any other in the United States. I don't have much more to add to the debate aside from my belief it is most likely not a valid reading when one looks at all the evidence. Normally when Death Valley records its hottest temperatures they occur during region-wide heat waves. On July 10, 1913 the next highest temperatures recorded in southern California (aside from Greenland Ranch) were just 119° at Heber and 118° at Mammoth Tank.


Figure 2. The instrument shelter at Greenland Ranch in 1926. (Photo from Bancroft Library Collection, Univ. of California, Berkeley).


Figure 3. The COOP form for Greenland Ranch in August 1924 shows some very suspicious readings with 16 nights above 100° including a 12-day consecutive stretch of such, including two at 110°! The modern (post 1934) record for Death Valley has never had more than 3 consecutive nights above 100° and a hottest night-ever of 104° on July 23-24, 2003.

VALIDITY SCORE: 5
This is a 50-50 proposition. The record was probably in error but it is difficult to 'prove' so. But using the criteria of old versus modern records one can see a problem with the 1913 record.

133° (56.1°C) date unknown In Salah, Algeria
SOURCE Extreme Weather; A Guide and Record Book by Christopher C. Burt
NOTES: I can find no reference for this reading anywhere in old or modern records. My bad for reporting it in my book Extreme Weather. The highest temperature in the old records for In Salah (1925-1950) indicate an absolute maximum of 122° and in the modern records an absolute maximum of 50.6° (123.1°F) was measured on July 12, 2002.
VALIDITY SCORE: 0
A mistake I made in my book. No temperature above 123.1°F has been officially recorded here. In fact, no temperature above 52°C has ever been recorded anywhere in the Sahara Desert in modern records.

131° (55.0°C) June (sometime between 1924-1942) Ghadames, Libya
SOURCE Libyan National Meteorological Centre
NOTES: Errors in keying in data for all of the 50°C+ recordings at Ghadames have been uncovered by the Libyan National Meteorological Center. For instance, a report of 54.2°C in June 1975 was actually 45.2°C and a 54.0°C reading in May 1969 was actually 45.0°C. Data for Ghadames prior to 1955 is considered unreliable because instrument exposure issues. The highest reliable temperature measured at Ghadames is 48.4°C (119.1°F) in July 1977.
VALIDITY SCORE: 1
Ghadames is not a particularly hot location in spite of old colonial temperature data. It has a good long record and the hottest modern (post 1960) temperature using good instruments has been just 119°F (48.3°C).

131° (55.0°C) date unknown Ben Gardene, Tunisia
SOURCE: World Survey of Climatology: Vol.10, Climates of Africa, p.42
NOTES: This site is on the Gefara Plain along the Mediterranean Sea as is Al Azizia, Libya and subject to the Ghibili (foehn-like) wind phenomena. However, no modern temperature above 124°F (52°C) has yet be measured here.
VALIDITY SCORE: 2
The older recordings by colonial stations used thermometers and shelters that probably cannot be accepted today. Furthermore, the modern records from this site do not support the possibility of such a high reading. See note below for Kibili.

131° (55.0°C) July 7, 1931 Kebili, Tunisia
SOURCE Service Meteorologique, Tunis
NOTES: There is a disconnect between many of the old (pre 1950) French and Italian colonial temperature records from many African weather stations versus the modern records at these same sites. Kebili is one of those. Between 1920-1933 Kebili reported 50-55°C maximum temperatures almost every summer. But since 2000 its absolute maximum has been only 48.5°C.
VALIDITY SCORE: 2
The older recordings by colonial stations involved thermometers and shelters that probably cannot be accepted today. Further more, the modern records from this site do not support the possibility of such a high reading. However, this particular site has a fractured history so far as its climate record is concerned and is subject to unusual heat waves thanks to the Sirocco wind events. A brief period of modern records from 2000-2010 has a 48.5°C (119.3°F) reading on July 26, 2005. But this is a long way from 55°C (131°F) measured during the 1920-1935 period of record).

130° (54.4°) Aug. 17, 1885 Amos (Mammoth Tank), California, USA
SOURCE: Climatology of California, U.S. Dept. Of Agriculture Bulletin L, 1903
NOTES: the Southern Pacific Railroad maintained several weather stations in the Colorado Desert region of southern California during the 19th century as watering stations for trains using their lines. It is likely that the thermometers and shelters and, most importantly, exposure location of these, was not up to official standards. Mammoth Tank, recorded 128°-130°F every summer between 1883 and 1887. After 1887 it would appear that there was some change in the instruments or shelter exposure since no temperature higher than 122° was reported (from 1887-1903). The old sites of Volcano Springs and Salton (now submerged under the waters of the Salton Sea) once reported temperatures of 129° (June 23, 1902) and 128° respectively.
VALIDITY SCORE: 2
Instruments were most likely overexposed.

130° (54.4°C) June (sometime between 1931-1940) Araouane, Mali
SOURCE: Service Meteorologique, Dakar
NOTES: Timbuktu has also supposedly recorded 130°F in the past (its modern record is 118° (47.8°C in May 1958). Once again, however, there is a disconnect between the colonial era temperature measurements and the modern-era ones (see Kibili, Tunisia note above). There is no weather station in Araouane now, but the hottest modern and reliable temperature in Mali is 48.2°C (119°F) at Gao in May 1988.
VALIDITY SCORE: 2
The older recordings by colonial stations involved thermometers and shelters that probably cannot be accepted today.

129.2° (54.0°C) June 21, 1942 Tirat Zvi, Israel
SOURCE: Bio-Climatic Atlas of Israel by Dr. D. Ashbel, Central Press, Jerusalem, 1950, p.125
NOTES: This is the most obvious error of all. The thermograph trace recording this temperature obviously peaked at 53°C (127.4°C) not 54°C (and two other nearby stations recorded only 52°C/126°F). But somebody wrote on it (with an arrow pointing at the peak, '54°'. They misread the thermograph as anyone can see on close examination. It is interesting that no one seems to have ever noticed this mistake before weather historian Howard Rainford pointed this out last summer; this has been widely accepted as the hottest temperature ever measured in Asia:


Figure 4. The thermograph trace recording the June 21, 1942 temperature at Tirat Zvi, Israel, shows that the temperature obviously peaked at 53°C (127.4°C) not 54°C. But somebody wrote on it (with an arrow pointing at the peak, '54°'. They misread the thermograph as anyone can see on close examination. Image credit: Bio-Climatic Atlas of Israel by Dr. D. Ashbel, Central Press, Jerusalem, 1950, p.125.

VALIDITY SCORE: 0
This was a very obvious error. Probable maximum temperature between 52-53°C (as recorded at two other sites nearby).

129° (53.9°C) July 7, 2007, July 20, 2005, and July 18, 1998 Furnace Creek, Death Valley, California, USA and also at Greenland Ranch, Death Valley on July 20, 1960
SOURCE: United States Weather Bureau (USWB)
NOTES: These readings are the highest reliably (and undisputed) temperatures yet recorded in the world.
VALIDITY SCORE: 10
These are measurements made under standard conditions using modern shelters and instruments.

ANECDOTAL TEMPERATURE REPORTS
188° (86.7°C) June or July, 1967 Abadan, Iran (heat burst)
SOURCE: News clip, no further info available. See Extreme Weather; A Guide and Record Book, by Christopher C. Burt, 2007, for more information on this event.
NOTES: This surely is an apocryphal record. The highest official temperature during the months of June or July 1967 at Abadan was 48.9°C (120°F) on July 15. Not an unusual temperature for this area at this time of the year.
VALIDITY SCORE: 0
Let.s think a moment just what kind of thermometer could have registered 188°F. An oven thermometer?

158° (70.0°C) July 6, 1949 near Lisbon, Portugal (heat burst)
SOURCE: News clip, no further info available. See Extreme Weather; A Guide and Record Book, by Christopher C. Burt, 2007, and Freaks of the Storm, by Randy Cerveny for more information on this event.
NOTES: The news reports of this event at the time claim this reading was made in the sun not shade. So it cannot be considered a reliable figure.
VALIDITY SCORE: 1
Well something amazing happened here this day but, again, just what kind of thermometer registers up to 158°F?

152° (66.7°C) July 10, 1977 Antalya, Turkey (heat burst)
SOURCE: News clip, no further info available. See Extreme Weather; A Guide and Record Book, by Christopher C. Burt, 2007, for more information on this event.
NOTES: The official maximum temperature at Antalya on July 10, 1977 was 43°C/109.4°F (and for that month 44°C/111.2°F on July 16). There is no reliable record concerning this 152° figure.
VALIDITY SCORE: 0
No evidence physical or otherwise about this event.

140° (60.0°C) June 15, 1960 Kopperl, Texas, USA (heat burst)
SOURCE: Tornadoes, Dark Days, Anomalous Precipitation and Related Weather Phenomena, William Corliss, Catalog of Geophysical Anomalies, 1983. See Extreme Weather; A Guide and Record Book, by Christopher C. Burt, and Freaks of the Storm, by Randy Cerveny, for more information on this event.
NOTES: a thermometer outside Kopperl's Bait and Tackle Shop reportedly measured this temperature around midnight following the collapse of nearby thunderstorms. The reliability of the thermometer in question is not known however very few common thermometers are capable of registering a temperature of 140°F.
VALIDITY SCORE: 4
Physical evidence (burnt crops) indicates an amazing heat burst occurred here, but the only thermometer to register it is in question.

140° (60.0°C) August, 1953 Delta, Baja, Mexico
SOURCE: Weather and Climate Extremes, Krause and Flood, US Army Corps of Engineers Technical paper TEC-0099, 1997
NOTES: The thermometer used for this reading was considered badly overexposed and this record is invalid.
VALIDITY SCORE: 2
We know it was a hot day and this region could perhaps record some incredible temperature. But 140°F?

140° (60.0°C) date unknown Riito, Sonora, Mexico
SOURCE: Weather and Climate Extremes, Krause and Flood, US Army Corps of Engineers Technical paper TEC-0099, 1997
NOTES: The thermometer used for this reading was considered badly overexposed and this record is invalid.
VALIDITY SCORE: 2
We know it was a hot day and this region could perhaps record some incredible temperature. But 140°F?

136.4° (58.0°C) Aug. 11, 1933 San Luis, Baja, Mexico
SOURCE: World Almanac 1980
NOTES: The thermometer used for this reading was considered badly overexposed and this record is invalid.
VALIDITY SCORE: 2
We know it was a hot day and this region could perhaps record some incredible temperature.

136° (57.8°C) July 11, 1909 Cherokee, Oklahoma, USA
SOURCE: Monthly Weather Review, USWB, July 1909 p. 337
NOTES: No information is known about the thermometer used for this reading and the temperature is therefore dismissed in the Monthly Weather Review mention of the event.
VALIDITY SCORE: 3
Physical evidence (burnt crops) indicates something amazing happened here that night, but the thermometer validity is a big question mark.

135° (57.2°C) July, 1989 Al-Amarha, Iraq
SOURCE: News clip (undetermined)
NOTES: The official maximum temperature measured at Al-Amarha for the month of July 1989 is only 49°C (120.2°F) on July 24. The 135°F reading is obviously a press exaggeration or was made in the sun.
VALIDITY SCORE: 0
Just a press exaggeration. No evidence whatsoever to support this.

133° (56.1°C) June 17, 1859 Santa Barbara, California, USA
SOURCE: The Coast Pilot of California, 1859
NOTES: There is no record of who made this measurement or exactly where it was made in Santa Barbara. Some later sources say it was made on a U.S. coastal geo-survey vessel. IF that is the case then the temperature is not possible since the waters off Santa Barbara in June are never warmer than about 70°F and any wind blowing over the ocean would have its temperature modified by the cool water no matter how hot the air.
VALIDITY SCORE: 1
This report is singular and there is physical evidence (burnt crops and dead animals) that something amazing happened here this day, but the temperature record is impossible to validate.

131° (55.0°C) Jan. 21, 1845 Interior of New South Wales, Australia
SOURCE: Monthly Weather Review, USWB, May 1930 p. 208
NOTES: This temperature is mentioned in passing as part of a discussion concerning hottest recorded temperatures from around the world. There is no further information known.
VALIDITY SCORE: 0
Old record and impossible to validate.

CONCLUSIONS CONCERNING ANECDOTAL RECORD TEMPERATURE REPORTS:
None of the above observations have ever been corroborated by other figures and are mostly the result of unofficial estimates or measurements made during heat bursts. They are all suspicious for one reason or another and cannot be taken too seriously and certainly not accepted as valid measurements.

CONCLUSIONS CONCERNING MEASURED RECORD TEMPERATURE REPORTS:
It would appear Death Valley, California holds the best authenticated value of 129°F and also the 2nd best 'possibly authentic' reading with the 134°F in 1913. I would propose that the hottest reliable, undisputed temperatures yet measured on earth are the 129°F (53.9°C) readings on four different occasions in Death Valley, California.

I think it also worth emphasizing the problems of the disconnect between old temperature data and modern temperature data from Africa (and elsewhere around the world). This makes it difficult to include anywhere on the continent of Africa among the 'possibly hottest' places on earth. There can only be two explanations for this;

1) The climate has become much cooler over the past 50 years in northern Africa, or,

2) The instruments and their shelters/locations during the first half of the 20th century were not as accurate as those used during the last half of the century. At least now we have the ability to double check suspicious data since it comes to us in real-time. Unfortunately, the old errors are harder to fix.

Kudos: to Maximiliano Herrera (who doesn't necessarily agree with what I have written above but nonetheless provided many useful facts and temperature data), and Howard Rainford.

References:

Too many to list. Please contact me for any specific references you would like to know.

Christopher C. Burt

Heat

Updated: 6:12 PM GMT on July 02, 2013

Permalink

A challenge to the validity of the world record 136.4°F (58°C) at Al Aziza, Libya

By: weatherhistorian, 1:50 PM GMT on October 08, 2010

QUESTIONS CONCERNING THE WORLD’S HOTTEST TEMPERATURE ON RECORD: 136.4°F (58°C) AT AL AZIZIA, LIBYA SEPTEMBER 13, 1922

One of the "sacred cows" of world weather extremes has been the widely reported "hottest temperature ever recorded on earth", a reading of 58°C (136.4°F) reported from Al Azizia, Libya on Sept. 13, 1922. There are many different spellings of this location:

al 'Aziziyah
El Azizia
El Azizya
Al Azizi
العزيزية


This figure has been controversial since it first appeared in publications of climate data by Italian colonial authorities in their publication Il Clima di Azizia, Tripolitanai by F. Erndia and reprinted in the Quarterly Journal of the Royal Meteorological Society, 1924 (p.324,) and in the German climate science journal Meteorologische Zeitschrift 1925, p.39. This data originated from the publication R. Ufficio Centrale di Meteorologia e Geodinamica; Osservazioni dell anno 1922 Rome, Italy. For an image of the cover of this book please see http://www.wmo.int/pages/mediacentre/news_members /documents/Libya.pdf.

However, its validity was first raised in an article that appeared in the U.S. Weather Bureau's Monthly Weather Review article published (unedited) in May 1930 (p.209) written by someone using the initials A.J.H.:

"At once it appeared to me as striking that a temperature so high should occur relatively near the sea and in a region of only semi desert character. A comparison with the remaining Tripolitanian stations in the R. Ufficio Agrario, Sezione Meteorogica, Nr. 4, and 5, showed that the reading is about 20° higher than the maxima on the same day and on the preceding day at other stations: Tripoli, 115°; Sidi Mesri, 111°; Homs, 112°; and Zuara Marina, 117°. Also in the year 1923, when the publication gives 135° as the maximum for Azizia, all of the remaining stations, nine in number, have maximum temperatures 18° or more degrees lower..."



THE SETTING:
Al Azizia is situated at an elevation of 158 meters (520 feet approximately) about 55 kilometers (25 miles) south and a bit west of Tripoli. It was a major trading center for the Sahel Jeffara region, hence its military significance prior to WW II.

The Tripolitania region of Libya is subject to a foehn phenomena locally known as a Ghibli wind, akin to the Santa Ana winds of Southern California, but in this case related to offshore breezes originating in the Sahara Desert that, when conditions warrant, is similar to Santa Anas; hot air from the interior is forced over the coastal hills and is compressed and heated by downward sloping along the shore line and foothills along the leeward slopes, in this case the Jabal Nafusah mountains (highest peak being about 750 meters (2,500 feet) in northwestern Libya.



Extreme maximum temperatures are the result. There is little doubt that the Ghibli wind phenomena was occurring on this date in Libya given the extreme temperatures reported from Tripoli (25 miles north by northeast of Al Azizia) and other locations in the coastal plain along the Mediterranean there. August and September are the months that these events are most common here, just as September and October are the months Santa Anas are most likely to form along the coast of Southern California. Note in the map above that the most of the known temperatures recorded on Sept. 13, 1922 were from coastal locations. However, during offshore foehn events interior locations are not necessarily hotter than coastal ones. Sidi Mesri, for instance (about 7 miles inland), was actually cooler than the Tripoli reading. It is highly unlikely that a reading some 20°F warmer could have occurred a further 18 miles inland from Sidri Mesri.

In this analysis I am only concerned about the extreme reading at Al Azizia.

EXAMINATION OF THE INSTRUMENT AND EXPOSURE:
In the 1950s Italian physical scientist A. Fantoli examined the thermometer and the shelter used in this world-record temperature observation. His conclusions were reported in two publications:

A. FANTOLI, I valori medi della temperatura in Libia, «Bollettino della Società Geografica Italiana», vol. 7, nn. 1-2 (1954), pp. 59-71.

A. FANTOLI, La più alta temperatura del mondo, «Rivista di Meteorologia Aeronautica», vol. 18, n. 3 (1958), pp. 53-63.

The crucial part of his reports concerned the exposure of the thermometer at the site and the thermometer itself :

1-Che se nel 1922 non si poté far altro che accogliere la cifra su esposta, del resto esplicitamente confermata, via radio, dall'autorità militare locale (el-Azizìa rimase per vario tempo isolata per ragioni contingenti) e quindi dalla scheda delle osservazioni, quando fu possibile raggiungere quel centro, si poté constatare che gli estremi termici erano stati ricavati mediante un termometro Six-Bellani essendosi guastato quello a massima della coppia ordinaria di dotazione»

2-La capannina con persiane semplici (abri, tipo inglese) veniva quindi a trovarsi a 5,5 metri dal suolo, a 48 circa sul piano medio della pianura circostante ed a 163 metri sul livello del mare. La base della capannina (isolata da tutte le parti) era stata fissata con staffe sul piano della terrazza, rivestito d'una copertura di cemento incatramato. Gli strumenti erano collocati nel modo usuale: anemoscopio e pluviometro situati a conveniente distanza; l'anemometro a mano (anemometro tipo Salmoiraghi) veniva portato in terrazza ad ogni osservazione.

This is translated as such (the language in his original report was of an archaic type and difficult to translate into English verbatim--italics indicate my own notes):

1- "So in 1922 you could not help but accept the figure on display, also explicitly confirmed by radio, by the local military (el-Aziz was isolated for some time for strategic reasons) and then by the observation log sheet when it was possible to see that data, you could see that the extreme heat was measured by a thermometer Six/Bellani having failed the other thermometer's "maximum potential" of the ordinary equipment (referring to, apparently, another thermometer on site that was not self-registering or capable of recording a value as high as 58°C). NOTE: The "Six/ Bellani" refers to this type of thermometer:

http://www.uniurb.it/PhysLab/strumenti/Heat.html

...and was used to record the 58°C since it was capable of being self-registering--.i.e. max and min temperatures recordings without human observation--unlike the "ordinary" thermometer apparently also in use at the site. The use of a self-registering instrument, such as this, throws more doubt on the observation implying that no human observation was made at the site that day).

2-The simple shelter with simple shutters (Abri, English type) (the term of an "abri English "type shelter" is not understood although "abri" is a French word for "shelter" perhaps he is just saying it was a standard shelter commonly used in Europe at that time) was fixed at 5.5 meters (sic) it must have been 5.5 feet not meters otherwise a 20 foot ladder must have been used to reach the shelter!) above the ground, at (an elevation) 48 meters above the surrounding plain, and at 163 meters above sea level. The base of the shelter (enclosed on all sides) (we will give the benefit of doubt here that the shelter was louvered as per a Stevenson screen) had been fixed by brackets on the floor of the terrace plaza, which was coated with a covering of tarred concrete. The instruments were placed in the usual way: anemometer and rain gauge located at a convenient distance away, the hand airspeed indicator (anemometer type Salmoiraghi) was taken on the terrace at every observation."

The key sentence being that the shelter "...was fixed on the surface of the terrace plaza which was covered by tarred concrete." The color of the concrete is not noted, but to the best of my knowledge most tarred concrete is black.

The WMO extreme weather records committee has this discussion concerning the measurement:

WMO Extreme Weather Records Committee Discussion
"An Italian weather station measured a temperature of 136.4°F (58°C) in al' Aziziyah (Azizia) Libya (about 25 miles south of Tripoli). Although this record has gained general acceptance as the world's highest temperature recorded under standard conditions, the validity of the extreme has been questioned. Fántoli (1954,1958) examined the record and researched the exposure, the instrument shelter, and the instruments themselves. A discussion in English of Fántoli's 1954 work appears in Gentilli, 1955. Fántoli generally concluded that the probable extreme maximum should have been only 132.8°F (56°C). Lamb (1958) noted that the extreme occurred following two days of hot, southerly winds and that latent heat may have been added to the air mass due to rain south of location."

HISTORY OF STATION:
Temperature records at this site were first established in 1919 by the Italian military at a farm 25 miles south of Tripoli. This farm may, in fact was almost certainly, being used as a military station. In 1926 the instruments were replaced and the location moved to a site nearby and put in civilian hands. Some references claim members of The National Geographic Society provided the instruments in 1913 (see "Change in the Weather" by Philip Eden p.195, The Daily Telegraph publishers, London, UK, 2005). Correspondence with NGS has indicated that this was not the case. They have no record of anyone from their organization providing such equipment at this time or at anytime in Libya. Here is correspondence received from them on March 8, 2010:

"Thank you for contacting the National Geographic Society.

The Society does not have meteorological stations. We reported on the highest temperature ever recorded at El Azizia; however, the recording equipment was not ours.

The World Meteorological Organization website indicates there is no information available on the actual equipment used to record the temperature:

http://www.wmo.int/pages/mediacentre/news_members /documents/Libya.pdf

I hope this information is helpful.

Sincerely yours,

Julie Crain
National Geographic Society."


After the location was moved, sometime in 1926, regular temperature data was supplied until 1942 when WWII interrupted such and the Italian authority was displaced.

The station was reestablished in 1947 following the war at the same site and continued in operation until 1984. In 2007 a new site was under construction for the weather station and the progress on this is undetermined.

STATISTICAL RECORD OF TEMPERATURES AT SITE:
Here is a chart of the extreme maximum monthly temperatures recorded at Al Azizia from 1920-1942 (centigrade):



Note the many extreme readings of 52°C+ (125.6°F) prior to 1927 and especially the 130°F+ readings in Aug. 1923, and Sept. 1923. No reading above 45.9°C (114.6°F) was recorded in September following the change in site and instrumentation. In fact the hottest post-1927 reading was 51.9°C (125.4°) in June 1928. Nine 50°C (122°F) readings were recorded between 1920 and 1926, with just 2 such from 1927 through 1942. The average absolute maximum temperature for September was 48.3°C (118.9°F) for the period of 1920-1926 and 42.4°C (108.3°F) for the period of 1927-1942. For August this average was 51.2°C (124.2°F) for 1920-1926 and 44.6°C (112.3°F) for 1927-1942. So the average absolute maximum temperatures for the period of 1920-1926 in August and September were some 10°F higher than for those same months in the 1927-1942 period of record.

(* Thanks to Khalid Ibrahim El Fadli, Libyan National Meteorological Center (LNMC) in Tripoli for this data.)

ANOMALY OF TEMPERATURE DATA AT SITE DURING PERIOD OF RECORD:
If one looks at the September average monthly temperature record for 1919-1940 one can see an anomaly in the pre-1927 record:



IMPORTANT UPDATE: This plot does not represent "average monthly temperature record" but mean daily temperature amplitude (difference between daily min and max) in September 1919-1940, and it's in degree Celsius.

Much higher values at 20s strongly suggests that there was exposure problem (minimum temperatures remained at normal levels, but maximum temperatures was increased which affected daily amplitudes)

Best Regards
Piotr Djakow (Mr. Djakow produced this graphic in an analysis of the Azizia record he recently posted in Polish). For a translation of this see the comments section and comment #23 by Neaplolitan.

CONCLUSIONS
The temperature observations at Al Azizia prior to 1927 (when the site and instruments were changed) are obviously invalid. The ONLY consideration to accept the 58°C figure is that this was a result of a heat burst from dissipating rain showers in the hills south of the site (as per the WMO conclusion noted before). However, this does not explain the other inconsistent readings in other months and years from the station prior to 1927. So this potential argument in favor of the reading on Sept. 13, 1922 is also invalid. Mr. Fantoli's recommendation of a lower more reliable reading of 132.8°F also does not stand up accordingly. The shelter housing the thermometer was most likely over exposed and measuring heat radiating of off the black-tarred concrete of the terrace on which it was placed. It is likely that the absolute maximum temperature conceivable at the site on this date was no more than 120°F at best. The highest authenticated temperature measured in Libya's modern records is a reading of 50.2°C (122.4°F) at Zuara in June of 1995.

NEXT DISCUSSION
So if Al Azizia, Libya's 58°C (136.4°F) is not the hottest reliably measured temperature in the world, what is?

Stay tuned to my blog the week of Oct. 18-25 for this.

REFERENCES
A. FANTOLI, I valori medi della temperatura in Libia, «Bollettino della Società Geografica Italiana», vol. 7, nn. 1-2 (1954), pp. 59-71.

A. FANTOLI, La più alta temperatura del mondo, «Rivista di Meteorologia Aeronautica», vol. 18, n. 3 (1958), pp. 53-63.

USWB, Monthly Weather Review, May 1930 p.209.

Eden, Philip, "Change in the Weather", Continuum Publishers, London, 2005 p.194-195.

"Weather and Climate Extremes" by Dr. Paul F. Krause and Kathleen L. Flood, US Army Corps of Engineers, Topographic Engineering Center, Report TEC-0099, 1997.

Al-Fenadi, Younis, Hottest Temperature Record in the World, El Azizia, Libya, Libyan National Meteorological Centre.

World Meteorological Organization (WMO) and Arizona State University World Weather Extremes Committee.

KUDOS
Thanks to Maximiliano Herrera, Piotr Djaków , Howard Rainford, Khalid Ibrahim El Fadli (Libyan National Meteorological Center), and Federico Noris (for translation of Fantoli notes) for their contributions to this article.

Christopher C. Burt

Heat

Updated: 2:36 PM GMT on October 23, 2011

Permalink

Super-Rainstorm Nicole

By: weatherhistorian, 2:34 PM GMT on October 02, 2010

For lack of a better moniker, I’m naming the super rainstorm which affected the Eastern Seaboard of the United States Sept. 26 - Oct. 1 after Tropical Storm Nicole, which supplied the stream of sub-tropical moisture that fueled this rain event. Tropical Storm Nicole itself dissipated well south of the Florida Peninsula on Sept. 29.

UPDATE: A number of vigilant readers have pointed out (correctly) that TS Nicole had only a tangental role in contributing to this rain event. As Dr. Masters emailed me "the rain event in NC was a PRE (Predecessor Rain Event) associated with the plume of moisture that accompanied Nicole, and very little of the rain was actually the remnants of Nicole". So, I guess, I should rename the storm as 'Super Rainstorm Diffluence Aloft'. Hmmm..doesn't have quite the cachet...!

The recent rainfall totals rival those of Hurricane Floyd (Sept. 15-17, 1999), the flooding from which was considered a 100-year event in many of the same places affected by this recent storm. The flooding was less severe this time around since the event was preceded by widespread drought conditions in most areas affected, and the rainfall from Floyd fell almost entirely within a 24-hour period for most locations; the ‘Nicole’ rainfall was spread over a three- to five-day period. Below is a chart comparison between the highest measured storm totals by state:



Some of the totals above are preliminary, COOP, CORAHS and spotter reports (as reported in the various NWS public information statements) and may not be final or official.

*NOAA has erroneously reported this total as 24.06”, but close examination of the COOP form for Southport indicates the actual total was 23.56”.

** NOAA reports this total as 14.00”, but the USGS states 12.59” was the total at this same site.


Figure 1. Rainfall totals from Hurricane Floyd of 1999. Image credit: NOAA/NCEP/HPC.


Figure 2. Rainfall totals for the 7-day period ending at 8am EDT October 2, 2010. Image credit: NOAA/AHPS.

Nicole references:

Wilmington, NC National Weather Service report

Floyd references:

NHC report on Hurricane Floyd
USGS report. "Two Months of Flooding in Eastern North Carolina, September - October 1999: Hydrologic Water-Quality, and Geologic Effects of Hurricanes Dennis, Floyd, and Irene"
USGS report, "Flooding in Delaware and the Eastern Shore of Maryland From Hurricane Floyd, September 1999"

Christopher C. Burt

Flood

Updated: 12:09 AM GMT on October 08, 2010

Permalink

About weatherhistorian

Christopher C. Burt is the author of 'Extreme Weather; A Guide and Record Book'. He studied meteorology at the Univ. of Wisconsin-Madison.