Christopher C. Burt is the author of 'Extreme Weather; A Guide and Record Book'. He studied meteorology at the Univ. of Wisconsin-Madison.
By: Christopher C. Burt , 8:04 PM GMT on May 22, 2012
The Wettest Places in the World
Last week I blogged about a new potentially wettest location in the United States (and thus also Oceania). However, new data has come to my attention indicating that a site in New Zealand may be even wetter than Hawaii’s wettest locations.
This is a brief survey of the wettest locations in the world. However, unlike Hawaii, it is difficult to find good up to date data for many of these locations. I have arranged the data by continents; from those with the wettest locations in the world to the ‘driest-wettest’ with the caveat of New Zealand.
A generalized map of global average annual precipitation.
Wettest locations in the World (Annual Average Precipitation)
Mawsynram, Meghalaya State, India 467.35”/11871 mm (wettest place in the world)
Cherrapunji, Meghalaya State, India 463.66”/11777 mm
Emei Shan, Sichuan Province, China 321.6”/8169 mm (wettest place in China)
Mawsynram (population about 350, elevation approximately 4,600’) and Cherrapunji (population about 10,000, elevation 4,309’ and also known as Sohra) are both located in the Khasi Hills on the Shillong Plateau of Meghalaya, India and are about 10 miles from one another. These are generally considered the wettest locations in the world for which there is measured data.
The Khasi Hills, wettest location in the world, are famous for the spectacular waterfalls that fall to the plains below. Photo source Wikipedia, photographer not identified.
The Khasi hills catch the full brunt of the southwest monsoon blowing off the Bay of Bengal between May and October. About 90% of their rain falls during this period. July alone averages over 120”/3050 mm, the highest monthly average rainfall in the world. Variability from one monsoon to another can be tremendous. Cherrapunji has had as much as 905”/22987 mm and as little as 282”/7163 mm in a single monsoon season (May–October) and as much as 1,041.78”/26461 mm in one year (August 1, 1860-July 31, 1861), a world record. What is amazing is that there was NO measurable rainfall that season (1860-1861) during November, December, February, and March (or the data was simply missing for those months—see table below).
Another world record, for monthly rainfall, was set here in July of 1861 when an astonishing 366.14”/9300 mm of rain fell (an average of 11.81”/300 mm for each day of the month!). The two-month period of June-July 1861 saw 502.63”/12767 mm of rainfall and the three-month period of May-July 644.44”/16369 mm (almost as much as the all-time annual record for Mt. Waialeale in Hawaii (683”/17347 mm)! An unverified source claims Mawsynram received 1,024.4”/26000mm) in 1985.
The mean of 463.66”/11777 mm at Cherrapunji is based on the POR of 1971-1990. Records here go back to 1851 (broken record) and the mean for the POR of 1851-1920 was 456.95”/11607 mm. For the POR of 2000-2010 Cherrapunji averaged 440.11”/11179 mm a year, and Mawsynram 477.88”/12138 mm.
This table shows the comparison of annual rainfall measured at Cherrapunji and Mawsynram between 1998-2010. Indian Meteorological Department.
For those interested in the actual raw data for Cherrapunji from 1851-1905 (there is a second page of data that continues to 1920 on page 247) I provide you with this table from ‘World Weather Records’, Smithsonian Miscellaneous Collections Vol. 79, p. 246 published by the Smithsonian Institute in 1929.
Tutunendo, Colombia 448.58”/11394 mm
Quibdo, Colombia 423.19”/10749
*(Lloro, Colombia estimate 523.6”/13300 mm)
The precipitation at Lloro is an estimated amount, the location being 14 miles southeast of Quibdo and at a higher elevation. Quibdo once recorded 781.06”/19839 mm in a single year, 1936. If the estimate for Lloro’s wetter location is correct, one might assume that during 1936 over 1,100”/27940 mm would have fallen at Lloro, which would have constituted an annual world record for precipitation. A web site claims that Tutendo received 1,036.34”/26323 mm in 1974. This cannot be verified.
Detailed precipitation data, like periods of record, are very difficult to come by for Colombia. The Colombian meteorological service (Instituto de Hydrologia, Meteorologia y Estudios Ambientales-IDEAM) has an impenetrable web site that demands a complex and byzantine user access application form. So the record for Lloro or other wet spots in Columbia locations (like Tutunendo) cannot be verified by myself.
The Colombian meteorological service (IDEAM) posts this map on its web site of Columbia’s average annual precipitation. Details are not available to the public.
Bahia Felix in Chile’s Tierra del Fuego has an average of 325 days a year with rain, the most in the world for a permanently inhabited location (some of the wetter remote Hawaiian Island sites probably exceed this figure). Bahia Felix averages 166.33”/4225 mm of precipitation a year. It is estimated that the wettest locations in this region at elevated parts near the southern tip of South America may reach 200-250”/5000-6500mm per annum.
Oceania (excluding New Zealand—scroll down further)
Big Bog, Maui, Hawaii 404.40”/10272 mm
Mt. Waialeale, Kauai, Hawaii 384.35”/9763 mm
Kukui, Maui, Hawaii 365.87"/9293 mm
All of these locations are uninhabited near mountaintops on their respective islands. See my last blog for details on Hawaii’s (and thus the U.S.A. and perhaps Oceania’s wettest locations). The figures above represent the amounts measured for the 30-year POR of 1987-2007 although for Big Bog the data from 1977-1992 was estimated.
An old photo from 1933 shows workers next to the 900-inch (28860 mm) capacity rain gauge they set up near the summit of Mt. Waialeale, perhaps the wettest location in the U.S.A. Photo from USGS archives.
Ureca, Bioko Island, Equatorial Guinea 411.42”/10450 mm
Debundscha, Cameroon 405.47”/10299 mm
The period of record for Ureca (also know as San Antonio de Ureca) was just 7 years during the 1930s or 1940s. Detailed precipitation data for Bioko Island (formerly known as Fernando Poo) in the Gulf of Guinea is no longer available. The wettest month is July when an average 86.81”/2205 mm of rain falls here.
Isohetyl map of Bioko Island (formerly Fernando Poo), a possession of Equatorial Guinea south of the coast of Cameroon. Ureca, on the southern tip of the island, is quite possibly the wettest location in Africa, and one of the wettest in the world. Map from ‘Climates of Africa’ World Survey of Climatology Vol. 10.
Debundscha, Cameroon is on the African mainland just north of Bioko on the coastline near Mt. Cameroon, a 13,435-foot peak (4095 meters). Deep moisture flowing in from the Gulf of Guinea and encountering Mt. Cameroon and the high peak of Bioko (Mt. Santa Isabel at 10,000 feet/3027 m) are what account for the extraordinary rainfall at these locations. Modern data is very hard to come by and the POR for Debubdscha is unknown. The figures I present here are from ‘Climates of Africa’ World Survey of Climatology Vol. 10, Elsevier Publishing Company, 1972 (pp. 284-289).
A map of Cameroon showing the location of Debundscha that rests at the southern foot of Mt. Cameroon. The island of Bioko can be seen in the Gulf of Guinea offshore.
Another location of potentially extreme rainfall is the volcanic highlands of Reunion Island in the Indian Ocean some 500 miles/800kilometers east of Madagascar. I cannot discern average annual rainfall amounts for the wettest locations and the intense rainfall here is almost always associated with tropical storms that occasionally traverse the island. For instance 212.60”/5400 mm of rain fell in one week at Commerson on February 24-March 2, 2007 and 73.62”/1871 mm at Cilaos in 24 hours on March 15-16, 1952. Both are world records for their respective time frames (not to mention the 52.76”/1340 mm in 12 hours at Belouve on February 28, 1964).
For a comprehensive look at all the extraordinary rainfall events on Reunion Island see my book ‘Extreme Weather: A Guide and Record Book’.
Australia and New Zealand
Bellenden Ker, Queensland, Australia 321.46” (8165 mm)
Bellenden Ker is located at an altitude of 5226 feet (1593 m) some 40 miles south of Cairns in Queensland. This is the 2nd highest mountain in the state. February is the wettest month with an average of 56” (1422 mm) of rainfall. A tropical storm in January 1979, produced almost 100” (2540 mm) of rain in just three days here and the total 212.09” (5387 mm) for that month is a record for Australia. In the year 2000, 490.59” (12461 mm) was measured, an annual record for the country. The POR for the average annual precipitation is for 1973-2011.
Cropp at Waterfall, South Island 453.38”/11516 mm
Milford Sound, South Island 245.2”/6228 mm
The gorgeous fiord of Milford Sound is one of New Zealand’s most popular tourist destinations and also long considered the country’s officially wettest location. It once received 22”/559 mm of rainfall in 24 hours on April 17, 1939. However, portions of the western Fiordland and Westland of the Southern Alps are estimated to receive as much as 630”/16000 mm of precipitation a year. If true some location there could be the wettest on earth.
Recent data for a RAWS site known as Cropps at Waterfall in Westland on the South Island (see map below) reported an average annual rainfall of 453.38”/11516 mm for the POR of 1982-2011. The location is situated at 43° 04’S, 171° 01’E. In 1998 the site reported 654.21”/16617 mm and for the 365-day period of Oct. 30, 1997-Oct. 29, 1998 and an amazing 724.60”/18405 mm. Its 24-hour record was 29.84”/758 mm on December 27-28, 1989. The site elevation is about 3,200’/975 m.
Here is a map showing the approximate location of Cropps at Waterfall, New Zealand, perhaps the wettest location on earth aside from the Khasi Hills of India. Map courtesy of the New Zealand National Institute of Water and Atmospheric Research (NIWA) from where the data for Cropps at Waterfall was also obtained. NIWA is the equivalent of the NCDC to the NWS in U.S. parlance.
Bowden Pen, Jamaica 307.9”/7821 mm
The recent POR for Bowden Pen is not known. This record dates from the 1940-1970 period.
Annual rainfall is estimated to be as high as 400”/10160 mm on the highest mountain peaks of the Caribbean Islands of Guadeloupe and Dominica. No actual weather sites have been established in these areas, past or present.
Henderson Lake, B.C., Canada 261.8”/6650 mm
Little Port Arthur, Alaska, U.S.A. 236.59”/6009 mm
Henderson Lake, British Columbia is located in the southwest of Vancouver Island on the south shore of Henderson Lake at an altitude of 20 feet (6 m). Its location is specified at 49° 2’N, 125° 1’W. Its wettest year on record was 1931 with 319.80”/8123 mm and wettest month December 1923 with 79.49”/2019 mm. The measurements were made at a fish hatchery that is no longer in operation. I do not know its complete POR, or the POR for the annual average precipitation mentioned above.
The POR for Little Port Arthur, Alaska is 1981-2010 for the figure presented, the most recent POR available, and makes this the wettest location in the United States outside of Hawaii. The site is located on the southern part of Baranof Island in southeast Alaska. Records here go back to 1936 although nobody seems to know much about the place. Its coordinates are 56° 23'N, 134° 39'W.
The wettest location in the contiguous United States, according to the latest NCDC records (POR 1981-2010), is 122.28”/3106 mm at Langlois, Oregon. Greater amounts are likely at isolated locations in the coastal mountain ranges of both Oregon and Washington.
Crkvica, Bosnia-Herzegovina 183.0”/4648 mm
The POR for this site is 22 years according to the WMO (exact years not provided). This site is located at 4298 feet (1310 m) in a mountain valley about 40 miles southwest of Sarajevo. There are probably wetter locations in Europe but nobody seems to have made any real effort to find such.
Crib Goch in Snowdonia, Wales U.K. is reported to average 168.58”/4282 mm a year (POR 1941-1970) making it the wettest location in Britain. However, British weather historian Stephen Burt comments further:
“In England, the central peaks of the Lake District are wettest, with an average annual rainfall something over 4000 mm/yr (157”). The gauge at Styhead (335 m AMSL) averaged 3947 mm/155.39” annually over 1941-70; the surrounding mountains receive perhaps 4500 mm/177”yr.
In Wales, the wettest places are around the summit of Snowdon, where a smaller area receives > 4000 mm/157”yr. The average at Llyn Llydaw may be very close to 5000 mm/197”yr.
In Ireland, there are several spots in Co. Kerry where the annual average exceeds 3000 mm/118”yr. Based upon the Met Éireann 1961-90 averages, the wettest gauged locations in Ireland were Mt Torc (Mangerton No. 3), at 808 m AMSL, at 3230 mm/127.16”yr, and Mt Ballaghbeama (311 m AMSL) with 3224 mm/126.93” annually. Both monthly gauges have over 50 years records.
Wettest of all are the mountains of western Scotland, where there are several areas with an annual average > 4000 mm/157”yr. The wettest is probably Glen Garry, where several gauges in the notoriously wet Kinlochquoich area received 4000-4200 mm/yr at even moderate altitudes, and some spots receive well over 5000 mm/197” most years. There are inevitable problems with rain gauges in remote, mountainous areas, not least the effects of snowfall and wind, but the records are probably as reliable and accurate as they can be, given the circumstances.
Except where indicated otherwise, all of these are based upon 1941-70 averages, which are the most recent rainfall averages to be published and mapped in any detail by the Met Office. Since that period western Scotland has become considerably wetter, and it's likely that more recent averaging periods will show average annual rainfall totals 20 per cent or more higher than the 1941-70 averaging period. The wettest gauged spots in western Scotland probably now receive around 5000 mm/197”yr, and the very wettest locations around 6000 mm/236”.
A map of the average annual precipitation for the United Kingdom (POR 1971-2000). Map courtesy of the UK Met. Office. To roughly convert inches to mm multiply the mm figure by .0394.
Obviously, the above information would indicate that it is quite possible that there may be locations in the British Isles that are wetter than the currently accepted Bosnian record for such in Europe.
Melchior, Antarctic Peninsula 46.81”/1189 mm
This is actually a group of small islands located off the very northern tip of the Antarctic Peninsula at 64°20’ S and 62°59’W (about as far north as the frozen continent extends). The POR is for 1947-1960 and made by an Argentinean base that was located there at that time.
The small island group of the Melchiors (various spellings) is located near the northern tip of the Antarctic Peninsula, the continent’s most northerly possession. The heart of the Antarctic continent is one of the driest locations on earth. Photo from Wikipedia, photographer unidentified.
The list below comprises all the wettest locations on earth that we have actual data for. This does not mean these are, in fact, the absolute wettest locations in the world. One may assume that there are even wetter spots beyond the reach of direct scientific observation and that over time certain places may become drier whereas others may become wetter.
The Top Ten Wettest Places in the World
1. 467.35”/11871 mm Mawsynram, Meghalaya State, India, Asia
2. 463.66”/11777 mm Cherrapunji, Meghalaya State, India, Asia
3. 463.40”/11770 mm Tutendo, Colombia, South America
4. 453.38”/11516 mm Cropp at Waterfall, New Zealand
5. 411.42”/10450 mm Ureca, Bioko Island, Equatorial Guinea, Africa
6. 405.47”/10299 mm Debundscha, Cameroon, Africa
7. 404.40”/10272 mm Big Bog, Maui, Hawaii, Oceania
8. 384.35”/9763 mm Mt. Waialeale, Kauai, Hawaii, Oceania
9. 365.87"/9293 mm Kukui, Maui, Hawaii, Oceania
10. 321.60”/8169 mm Emei Shan, Sichuan Province, China, Asia
*(estimate 523.6”/13300 mm Lloro, Colombia, South America)
KUDOS: Blair Trewin for Australian and New Zealand data and Stephen Burt for his insights on precipitation in the United Kingdom and Ireland.
(P.S. I will be away on holiday until June 1, so this will be my last post for the next two weeks).
Christopher C. Burt
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