Japan Sets its All-Time Heat Record: 41.1°C (106°F)

July 23, 2018, 5:06 PM EDT

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Above: Families swim and play in the water at a seaside park in Tokyo on July 22, 2018, as the temperature neared 40°C (104°F) in many cities on July 22. Photo credit: Kazuhiro Nogi/AFP/Getty Images.

A scorching heat wave that has cooked Japan since the second week of July brought the country its hottest temperature ever recorded on Monday, July 23: 41.1°C (106°F) at Kumagaya. Kumagaya is located in the Saitama prefecture, about 40 miles (65 km) northwest of Tokyo. The previous all-time heat record in Japan was 41.0°C (105.8°F) in Ekawasaki on the island of Shikoku on August 12, 2013. At least 13 stations in Japan set a new all-time heat record on Monday (see tweet below).

Japan record heat

Figure 1. A department store employee places numbers showing a temperature of 41.1 degrees Celsius on a large thermometer board in Kumagaya, Saitama prefecture on July 23, 2018, which set a new all-time record for the hottest temperature ever measured in Japan. Image credit:  JIJI PRESS/AFP/Getty Images.

Extreme heat since July 14 in Japan and Korea

An extreme and unusually persistent kink in the jet stream brought a very strong ridge of high pressure to east Asia beginning around July 14, when all-time heat records started falling. The heat wave is being blamed for at least 10 heat-related deaths in Korea and 77 in Japan, where 30,000 heat-stroke hospitalizations have also occurred. Beginning on July 14, Kyoto, Japan (where weather records extend back to 1881) proceeded to beat its previous all-time high for July (38.3°C/101.0°F from July 26, 2014) on six out of seven days, culminating on July 19 with 39.8°C (103.6°F), a tie for its all-time high temperature for any month (previously set on August 8, 1994):

38.5°C (101.3°F) on Saturday, July 14
38.7°C (101.7°F) on Sunday, July 15
38.5°C (101.3°F) on Monday, July 16
39.1°C (102.4°F) on Wednesday, July 18
39.8°C (103.6°F) on Thursday, July 19
38.6°C (101.5°F) on Friday, July 20

Over the weekend (July 21 – 22), a number of stations in North and South Korea set their all-time heat records (thanks go to Maximilliano Herrera and Etienne Kapikian for researching these records):

36.6°C at Boeun, South Korea, July 21
39.7°C at Wonsan, North Korea, July 22 (1.7C above its previous all-time record in July 1977)
32.9°C at Taegwalliong, South Korea (842m elevation), July 22
37.5°C at Suwon, South Korea, July 22

One more day of extreme heat for central Japan

The ridge of high pressure that brought Japan its all-time heat record will stay strong one more day, with the temperature again expected to exceed 100F in Kumagaya on Tuesday. By Wednesday, though, the ridge will weaken, as an upper-level low pressure system over Kamchatka, Russia drifts to the southwest towards Japan. This should put an end to record-breaking temperatures in central and northern Japan, though southern Japan and Korea may continue to see record-breaking heat through the end of the week.

Four all-time national heat records broken in 2018

Japan is now the fourth nation to break an all-time record in 2018 for hottest temperature in recorded history:

Japan, 106°F  (41.1°C) at Kumagaya on July 23.
Palau, 95°F (35°C) at Koror on June 22.
Taiwan, 104.5°F (40.3°C) at Tianxiang on July 10.
Algeria, 124.3°F (51.3°C) at Ouargla on July 5.

No nations have set an all-time cold temperature record so far in 2018. 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, 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.

More nations set all-time highs in 2016 than in any other year

Setting an all-time heat record is easier to do if the planet happens to be experiencing its warmest year on record. In 2018, Earth has had its fourth warmest year-to-date period on record, and we are seeing far fewer all-time heat records than we did in 2016, which was Earth’s warmest year on record. From January through December 31, 2016, a total of 22 nations or territories tied or set all-time records for their hottest temperature in recorded history. The previous record was eighteen all-time heat records in 2010. Here were 2016's all-time heat records (courtesy of Maximiliano Herrera):

The Comoros: December 22, 2016, 35.6°C (96.1°F) at Hahaya Airport (tie).
French Guiana : September 27, 2016, 38.0°C (100.3°F) at Saint Laurent du Moroni.
The Marshall Islands: August 24, 2016, 35.6°C (96.1°F) at Utirik Atoll.
The Cayman Islands (United Kingdom territory) : August 21, 2016, 34.9°C (94.8°F) at Owen International Airport (tie).
The British Virgin Islands [United Kingdom territory]: July 22, 2016, 35.0°C (95.0°F] at Terrance B. Lettsome International Airport.
Iraq: July 22, 2016, 53.9°C (129.0°F) at Basrah.
Iran: July 22, 2016, 53.0°C (127.4°F) at Delhoran (tie).
Kuwait : July 21, 2016, when the mercury hit 54.0°C (129.2°F) at Mitribah.
Guernsey (United Kingdom territory): July 19, 2016, 35.0°C (95°F) at the small island of Alderney (tie).
Hong Kong Territory (China): July 9, 2016, 37.9°C (100.2°F) at Happy Valley (tie).
Niger: June 8, 2016, 49.0°C (120.2°F) at Bilma.
Palau: June 8, 2016, 34.4°C (93.9°F) at Koror AWS (tie).
India : May 19, 2016, 51.0°C (123.8°F) at Phalodi.
Maldives: April 30, 2016, 35.0°C (95.0°F) at Hanimaadhoo.
Thailand: April 28, 2016, 44.6°C (112.3°F) at Mae Hong Son.
Cambodia: April 15, 2016, 42.6°C (108.7°F) at Preah Vihea.
Burkina Faso: April 13, 2016, 47.5°C (117.5°F) at Dori.
Laos: April 12, 2016, 42.3°C (108.1°F) at Seno.
Vanuatu in the South Pacific: February 8, 2016, 36.2°C (97.2°F) at Lamap Malekula.
Tonga: February 1, 2016, 35.5°C (95.9°F) at Niuafoou.
Wallis and Futuna Territory (France): January 10, 35.8°C (96.4°F) at Futuna Airport. 
Botswana: January 7, 2016, 43.8°C (110.8°F) at Maun.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

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Dr. Jeff Masters

Dr. Jeff Masters co-founded Weather Underground in 1995 while working on his Ph.D. in air pollution meteorology at the University of Michigan. He worked for the NOAA Hurricane Hunters from 1986-1990 as a flight meteorologist.


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