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July 2015: Warmest Month on Record Globally

By: Jeff Masters and Bob Henson 9:56 PM GMT on August 20, 2015

The Atlantic and Pacific tropics were buzzing with activity on Thursday (see bottom of this post for a very brief update), but Thursday brought other big news as well: July 2015 was the warmest single month in 1627 months of global records that go back to January 1880, said NOAA's National Centers for Environmental Information (NCEI). The globally averaged temperature above both land and ocean surfaces was 1.46°F (0.81°C) ahead of the 20th-century average. This trumps the record for any month that was set in July 1998, surpassing that value by 0.08°F (0.14°C). On average, July is the warmest month of the year globally, tpyically driven by midsummer conditions across the Northern Hemisphere’s extensive land areas. However, according to NOAA, record warmth across much of the Pacific and Indian oceans played a major role in July’s new global record. NASA also rated July 2015 as the warmest July on record. July 2015's warmth makes the year-to-date period (January - July) the warmest such period on record, according to both NOAA and NASA. A potent El Niño event in the Eastern Pacific that crossed the threshold into the "strong" category in early July continues to intensify, and strong El Niño events release a large amount of heat to the atmosphere, typically boosting global temperatures by at least 0.1°C. This extra bump in temperature, when combined with the long-term warming of the planet due to human-caused emissions of heat-trapping gases like carbon dioxide, makes it extremely likely that 2015 will be Earth's second consecutive warmest year on record.

Figure 1. Departure of temperature from average for July 2015, the warmest single month for the globe since record keeping began in 1880. Large areas of record warmth were analyzed across many parts of the Indian and Pacific oceans, as well as in northern South America, southeast Africa, and parts of southern Europe. Image credit: National Centers for Environmental Information (NCEI) .

Global satellite-measured temperatures in July 2015 for the lowest 8 km of the atmosphere were the 10th warmest in the 37-year record, according to the University of Alabama Huntsville (UAH). The lowest 8 km of the atmosphere heats up dramatically in response to moderate to strong El Niño events, with a time lag of several months--as occurred during the El Niño events of 1998 and 2010. Thus, we should see Earth's lower atmosphere temperature hit record levels late this year and/or early in 2016.

Deadliest weather disaster of July 2015: monsoon floods in Asia
The deadliest weather-related disaster of July 2015 was flooding in Asia due to the annual monsoon, which claimed over 200 lives in Pakistan, Myanmar, Afghanistan, Bangladesh, Vietnam, India, and China. Severe flooding in these countries continued during the first ten days of August, bringing the total monsoon death toll to over 400, as reported by Bob Henson in his August 11 post.

Figure 2. Navigating a flooded area of Peshawar, Pakistan, on July 26, 2015. Torrential rains and floods in Pakistan left 36 dead and affected more than 250,000 people, disaster management officials said July 25, with swollen rivers and water channels damaging hundreds of villages. Photo credit: A Majeed/AFP/Getty Images.

Two billion-dollar weather disasters in July 2015 in China
Two billion-dollar weather-related disasters hit the Earth last month, both in China, according to the July 2015 Catastrophe Report from insurance broker Aon Benfield: Typhoon Chan-hom ($1.6 billion in damage) and flooding July 20 - 24 that caused $1.2 billion in damage. With twelve billion-dollar weather disasters so far in 2015, Earth is on pace for its lowest number of such disasters since 2004, when sixteen occurred.

Disaster 1. Typhoon Chan-hom made landfall about 80 mi south-southeast of Shanghai, China on July 11, killing 16 people and doing at least $1.5 billion in damage. The typhoon did another $100 million in damage to Guam, Japan, Taiwan, and Korea. In this image, we see people watching huge waves from Chan-hom pounding Wenling, in east China's Zhejiang province, on July 10, 2015. Image credit: STR/AFP/Getty Images.

Disaster 2. Heavy rainfall in China from July 20 - 24 killed 28 people and did $1.2 billion in damage. More than 238,000 residents were evacuated as floods and landslides destroyed 7,770 homes and damaged 35,100. In this picture, we see vehicles stranded on a flooded road in Wuhan, Hubei Province of China, on July 23, 2015, when 160.2 millimeters (6.31") hit the city. This was their heaviest daily rainfall since 1998, according to Changjiang Times. Image credit: ChinaFotoPress/Getty Images.

Arctic sea ice falls to 8th lowest July extent on record
Arctic sea ice extent during July 2015 was the 8th lowest in the 36-year satellite record, according to the National Snow and Ice Data Center (NSIDC). A large area of high pressure set up shop north of Alaska, and a strong area of low pressure formed over Northeastern Eurasia. The circulation around these features brought sunny skies and a warm flow of air into the Arctic that led to rapid ice loss. This Arctic Dipole pattern also occurred in all the summer months of 2007, and helped support the record 2007 summer reduction in sea ice extent. (Note that the record was beaten in 2012, a year that did not feature an Arctic Dipole pattern.) The Arctic Dipole pattern diminished in early August 2015, but substantial melting has continued into the middle of the month.

Notable global heat and cold marks set for July 2015
Hottest temperature in the Northern Hemisphere: 52.8°C (127.0°F) at Mitribah, Kuwait, July 30
Coldest temperature in the Northern Hemisphere: -22.5°C (-8.5°F) at Summit, Greenland, July 30
Hottest temperature in the Southern Hemisphere: 37.6°C (99.7°F) at Floriano, Brazil, July 10
Coldest temperature in the Southern Hemisphere: -80.2°C (-112.4°F) at Dome A, Antarctica, July 2

Major stations that set (not tied) new all-time heat or cold records in July 2015
Akkuduk (Kazakhstan) max. 46.8°C July 1
Boulogne sur Mer (France) max. 35.4C° July 1
Melun (France) max. 39.4°C July 1
Dieppe (France) max. 38.3°C July 1
Urumita (Colombia) max. 42.2°C July 1
Dzhusaly (Kazakhstan) max. 46.2°C July 2
Volkel (Netherlands) max. 36.9°C July 2
Twenthe (Netherlands) max. 36.1°C July 2
Leeuwarden (Netherlands) max. 34.0°C July 2
Valledupar-Villa Rosa (Colombia) max. 42.4°C July 3
Bad Lippspringe (Germany) max. 37.9°C July 4
Giessen (Germany) max. 38.1°C July 4
Repelon (Colombia) max. 40.9°C July 4
Frankfurt (Germany) max. 39.0°C July 5
Ohringen (Germany) max. 38.5°C July 5
Wurzburg (Germany) max. 38.6°C July 5
Kiztingen (Germany) max. 40.3°C July 5, New national record high for Germany
Kahl (Germany) max. 39.8°C July 5
Bad Durkheim (Germany) max. 39.7°C July 5
Neunkirchen (Germany) max. 39.2°C July 5
Hannover City (Germany) max. 39.0°C July 5
Aigle (Switzerland) max. 36.1°C July 5
Gerona Airport (Spain) max. 41.3°C July 5
Gerona St Daniels (Spain) max. 42.2°C July 5
Cienfuegos (Cuba) max. 37.0°C July 6
Barcelonette (France) max. 34.3°C July 6
Mende (France) max. 36.1°C July 6
Gap (France) max. 36.9°C July 6
Saint-Martin-d’Heres (France) max. 40.7°C July 7
Lezigneux (France) max. 39.9°C July 7
Embrun (France) max. 36.7°C July 7
St Etienne (France) max. 41.1°C July 7
Sainte-Leocadie (France) max. 35.4°C July 7
Grenada Airport (Spain) max. 43.1°C July 7
Grenada City (Spain) max. 43.9°C July 7
Lerida (Spain) max. 43.1°C July 7
Zaragoza (Spain) max. 44.5°C July 7
Geneva (Switzerland) max. 39.7°C July 7
Nyon/Changins (Switzerland) max. 38.0°C July 7
Payerne (Switzerland) max. 37.9°C July 7
Neuchatel (Switzerland) max. 37.8°C July 7
Fribourg (Switzerland) max. 36.6°C July 7
Neuenburg (Switzerland) max. 37.8°C July 7
Wynau (Switzerland) max. 37.2°C July 7
Evolene (Switzerland) max. 28.4°C July 7
Plaffeien (Switzerland) max. 32.0°C July 7
La Fretaz (Switzerland) max. 29.9°C July 7
Oberstdorf (Germany) max. 35.6°C July 7
Innsbruck City (Austria) max. 38.2°C July 7
Qaanaaq (Greenland/Denmark) max. 20.4°C July 8
Ardebil (Iran) max. 40.2°C July 10
Jucaro (Cuba) max. 36.8°C July 10
Riohacha (Colombia) max. 40.6°C July 13
Yuzawa (Japan) max. 36.8°C July 13
Washikura (Japan) max. 29.0°C July 13
Tajima (Japan) max. 34.8°C July 13
Niitsu (Japan) max. 37.9°C July 13
Ogata (Japan) max. 38.3°C July 13
Uozu (Japan) max. 37.9°C July 13
Nanao (Japan) max. 37.4°C July 13
Yamada (Japan) max. 37.5°C July 14
Kasenuma (Japan) max. 36.7°C July 14
Marumori (Japan) max. 37.6°C July 14
Yanagawa (Japan) max. 39.1°C July 14
Kawauchi (Japan) max. 35.7°C July 14
Ononimachi (Japan) max. 35.8°C July 14
Buzaubaj (Uzbekistan) max. 48.2°C July 14
Limoges Airport (France) max. 37.3°C July 16
Grazzanise (Italy) max. 39.8°C July 17
Split Airport (Croatia) max. 39.4°C July 18
Krems (Austria) max. 38.3°C July 19
Senj (Croatia) max. 39.7°C July 22
Rab (Croatia) max. 39.3°C July 22
Zadar Airport (Croatia) max. 39.0°C July 22
Zavizan (Croatia) max. 28.3°C July 22
Ronchi dei Legionari (Italy) max. 39.2°C July 22
Aviano (Italy) max. 38.3°C July 22
Vsetin (Czech Republic) max. 36.8°C July 22
Osako (Japan) max. 36.4°C July 22
Esashi (Japan) max. 37.2°C July 22
Kanayama (Japan) max. 36.1°C July 22
Altai (China) max. 39.5°C July 22
Hoboksar (China) max. 37.7°C July 22
Kaba He (China) max. 41.0°C July 22
Korla (China) max. 40.5°C July 24
Jucaro (Cuba) max. 37.0°C July 28
Contramaestre (Cuba) max. 38.2°C July 29
Isabel Rubio Airport (Cuba) max. 36.3°C July 29
Indio Hatuey (Cuba) max. 38.1°C July 30
Kirkuk (Iraq) max. 50.0°C July 30
Najaf (Iraq) max. 51.5°C July 30
Kanaqin (Iraq) max. 52.0°C July 30
Salahaddin (Iraq) max. 41.1°C July 31
Meigetsu (Japan) max. 37.8°C July 31
Vize Island (Russia) max. 9.2°C July 31

New all-time national and territorial heat records set or tied in 2015
As of August 14, 2015, ten nations or territories tied or set all-time records for their hottest temperature in recorded history in 2015, and one (Israel) set an all-time cold temperature record. For comparison, only two nations or territories set all-time heat records in 2014, and nine did in 2013. The most all-time national heat records held by any year is nineteen in 2010. Most nations do not maintain official databases of extreme temperature records, so the national temperature records reported here are in many cases not official. I use as my source for international weather records researcher Maximiliano Herrera, one of the world's top climatologists, who maintains a comprehensive list of extreme temperature records for every nation in the world on his website. If you reproduce this list of extremes, please cite Maximiliano Herrera as the primary source of the weather records. Wunderground's weather historian Christopher C. Burt maintains a database of these national heat and cold records for 235 nations and territories on wunderground.com's extremes page. Here are the all-time national or territorial heat and cold records set so far in 2015:

Hong Kong set its national heat record on August 9, when the mercury hit 37.9°C (100.2°F) at Happy Valley.
Germany set a new national heat record of 40.3°C (104.5°F) twice this year: on July 5 and on August 7, at the Kitzingen station in Bavaria.
Vietnam tied its national heat record of 42.7°C (108.9°F) at Con Cuong on May 30.
Palau tied its national heat record of 34.4°C (94.0°F) at Koror Airport on May 14.
Venezuela set a new national heat record of 43.6°C (110.5°F) at Coro on April 29.
Laos tied its national heat record of 42.0°C (107.6°F) at Thakhek on April 20.
Ghana set a new national heat record of 43.3°C (109.9°F) at Navrongo on April 10. This is the third time this year Ghana has tied or set a new all-time heat record.
Cocos Islands (Australian territory) tied their all-time heat record with 32.8°C (91.0°F) on April 8.
Equatorial Guinea set a new national heat record of 35.5°C (95.9°F) at Bata on March 17.
Wallis and Futuna Territory (France) set a new territorial heat record with 35.5°C (95.9°F) on January 19 at Futuna Airport.

Israel set a new national cold record of -14.2°C (6.4°F) at Merom Golan on January 10.

Special Mentions:
Antarctica set a new heat record for its mainland of 17.5°C (63.5°F) at Esperanza Base on March 24. Previous record: 17.4°C (63.3°F) at Marambio Base, set the previous day. The World Meteorological Organization (WMO) has appointed a committee to study this event and determine if this represents an official record for the continent. Note that this is a record for mainland Antarctica, not a territorial or continental record. The all-time maximum record for the continent and territory of Antarctica is 19.8°C (67.6°F) on January 30, 1982, in Signy Island, South Orkney, an island group located about 450 miles northeast of the tip of the Antarctic Peninsula, the northernmost portion of mainland Antarctica. Geologically, the South Orkney are on the Antarctic plate, and politically, they are part of Antarctica. This record was improperly listed as a territorial record for Antarctica in May's global summary.

Switzerland had its highest reliably measured temperature on record in Geneva on July 7, when the mercury hit 103.5°F (39.7°C). The only higher temperature ever measured in the country was a 106.7°F (41.5°C) reading on August 11, 2003 at Grono. As reported at the Swiss news site swissinfo.ch, this old record was achieved "using an old measurement technique of weather huts, which generally recorded temperatures a few degrees higher than modern instruments." Weather records researcher Maximiliano Herrera agrees that this year's 39.7°C reading in Geneva is the highest reliably measured temperature ever in Switzerland, though the August 11, 2003 temperature at Grono was probably warmer (near 40°C), after correcting for the known problems with the site.

Samoa was originally listed by Mr. Herrera as tying its national heat record with 36.5°C (97.7°F) on January 20 at Asau, but a subsequent review of the record revealed possible issues with the measurement equipment, so this record is dubious.

Kudos also to Mr. Herrera for supplying the data for the "Notable global heat and cold marks set for July 2015" and "Major stations that set (not tied) new all-time heat or cold records in July 2015" sections.

Danny strengthens slightly; 93C likely to become Hurricane Kilo and approach Hawaii
Tiny Hurricane Danny continues to gradually strengthen in the central Atlantic. At 5:00 p.m. EDT, Danny’s top sustained winds were up to 80 mph. Danny was still located far out to sea—more than 1000 miles east of the Windward Islands, moving west-northwest at just 10 mph—and there are no major changes to the outlook for Danny from our post this morning. Meanwhile, Invest 93C has been upgraded to Tropical Depression 3 in the central Pacific, and the Central Pacific Hurricane Center projects TD 3-C to become Hurricane Kilo by Saturday, perhaps curving toward the western Hawaiian islands as a Category 2 hurricane by Monday. We’ll have a full update on both systems by 1 PM ET Friday. See also Steve Gregory’s update from earlier this afternoon.

Jeff Masters and Bob Henson

Climate Summaries Climate Change

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.