October 2024 was Earth’s second-hottest October on record, according to an analysis of global data going back to 1850, NASA and NOAA’s National Centers for Environmental Information reported November 13. The month fell just 0.05 degree Celsius (0.09°F) below the record set in October 2023. Both October 2023 and October 2024 came in well above all preceding Octobers, and the past 11 Octobers have all been warmer than any others on record.
As opposed to being focused in one region or another, the record heat was unusually widespread. About 12.2% of the world’s surface experienced record heat, beating the previous October record extent set in 2015 of 8.4%.
NASA placed October at 1.55 degrees Celsius (2.79°F) above the 1880-1899 period, its best estimate for when preindustrial temperatures last occurred. This fell below the previous October record (from 2023) by a scant 0.02 degree Celsius (0.04°F). The European Copernicus Climate Change Service also rated October 2024 as the second-warmest October on record.
Land areas had their warmest October on record in 2024, according to NOAA, and global ocean temperatures were the second-warmest on record. The recent record heat in the oceans in 2024 has brought on a global coral bleaching event, the fourth one in recorded history (1998, 2010, 2014-17, and now 2024).
It was the warmest October on record for North America, second-warmest for South America and Oceania, fourth-warmest for Europe, fifth-warmest for Asia, and 10th-warmest for Africa.
Extraordinary heat in the tropical Atlantic
The Caribbean had its warmest October on record, and the Atlantic Main Development Region for hurricanes (from the coast of Africa to the Caribbean, between 10°N and 20°N) had its second-warmest October, behind 2023. For the three-month August through October peak of the Atlantic hurricane season, sea surface temperatures during 2024 in the Main Development Region were the second-warmest on record, behind only 2023 (Fig. 2). Both 2023 and 2024 had sea surface temperatures far in excess of any previous year – much higher than can be explained by the century-long increasing trend of 1.09 degrees Celsius (1.96°F). Unusual atmospheric circulation patterns made a significant contribution to this extraordinary warmth in 2023 and 2024. There is no way to know if this shift in weather patterns will continue in the coming years, potentially ushering in a new era of unusual intense hurricane activity. There is a risk that a tipping point has been crossed that will make the abnormally warm tropical Atlantic sea surface temperatures of 2023-2024 commonplace, but it is more likely that 2023-2024 was an anomaly that will not be seen again for many years.
For the year to date, the January-to-October global surface temperature ranked warmest in NOAA’s 175-year record. According to NOAA/NCEI’s statistical analysis, there is a greater than 99% chance that 2024 will rank as the warmest year on record, which would give the planet two consecutive warmest years on record. It appears unlikely Earth will again see a year in the 20th-century temperature range for many years to come, unless there is major volcanic cooling, a major geoengineering push, and/or a sustained, worldwide effort to reduce fossil-fuel emissions.
Second-warmest October on record for the contiguous U.S.
As detailed by Bob Henson in our post on Friday, the contiguous U.S. had its second-warmest October on record. Furthermore, the autumn of 2024 to date (the period September-October) is by far the warmest in contiguous U.S. history, running almost a full degree Fahrenheit above September-October 2015. In addition, October 2024 was tied with October 1963 and November 1917 as the second-driest month in 130 years of record-keeping for the contiguous U.S.; only October 1952 was drier.
The inflation-adjusted tally of U.S. billion-dollar weather disasters so far in 2024 has been 24. These include 17 severe storm events, four hurricanes, one wildfire, and two winter storms. Drought costs thus far in the U.S. amount to $1.7-$2 billion (according to Gallagher Re and Aon), so NOAA will likely be adding another billion-dollar disaster from drought. The average number of billion-dollar disasters for a full year for the most recent five years (2019–2023) is 20.4; the record was 28, set in 2023.
Both global fossil fuels and total CO2 emissions at record levels in 2024
Heat-trapping carbon dioxide emissions from fossil fuels and cement production will rise around 0.8% in 2024, reaching a record 37.4 billion tons of carbon dioxide, according to the 2024 Global Carbon Budget report by the Global Carbon Project, released November 12. The 0.8% annual increase is roughly on par with the 0.9% average annual increase during the 2010s.
Total carbon dioxide emissions, which include land-use change, are also expected to reach record highs, 2% above the previous record set in 2023. This large increase was driven both by growth in fossil-fuel emissions and abnormally high land-use emissions in 2024 – in part, from wildfires in South America worsened by a strong El Niño event and record high temperatures.
A La Niña watch in effect
The 2023-24 El Niño event in the Eastern Pacific ended during May, and neutral conditions remain in place, NOAA reported in its latest October 10 monthly discussion of the state of the El Niño/Southern Oscillation, or ENSO. A new outlook is scheduled to be released November 14. La Niña is still projected to prevail during 2024-25, but the slower-than-expected pace of development thus far has chipped away slightly at the probabilities in recent months.
According to the official NOAA probabilistic forecast, which is based on expert judgment drawing from observations and model data, La Niña conditions are expected to occur during the Northern Hemisphere winter of 2024-2025, with a 74% chance during November-January. The most likely outcome is a weak La Niña event rather than a moderate or strong one.
Arctic sea ice: 4th-lowest October extent on record
Arctic sea ice extent during October 2024 was the fourth-lowest in the 46-year satellite record, according to the National Snow and Ice Data Center. The Arctic had its third-warmest October on record. Antarctic sea ice extent in October was the second-lowest on record, well below all other years except for 2023. The Antarctic region had its second-warmest October on record.
Notable global heat and cold marks for October 2024
The information below is courtesy of Maximiliano Herrera. Follow him on Twitter @extremetemps:
- Hottest temperature in the Northern Hemisphere: 47.2°C (117.0°F) at Palm Springs and Indio, U.S., October 1, and Ejido Nuevo Leon, Mexico, October 6;
- Coldest temperature in the Northern Hemisphere: -52.9°C (-63.2°F) at Summit, Greenland, October 29;
- Hottest temperature in the Southern Hemisphere: 47.0°C (116.6°F) at Villamontes, Bolivia, October 7; and
- Coldest temperature in the Southern Hemisphere: -73.1°C (-99.6°F) at Dome Fuji, Antarctica, October 11.
Major weather stations in October: 14 all-time heat records, 0 all-time cold records
Among global stations with a record of at least 40 years, 14 set, not just tied, an all-time heat record in October; no stations set an all-time cold record:
Cayenne AP (French Guiana, France) max. 35.6°C, October 2;
Peixe (Brazil) max. 42.5°C, October 3;
Alto Parnaiba (Brazil) max. 41.9°C, October 5;
Goias (Brazil) max. 44.5°C, October 6;
Aquidauana (Brazil) max. 43.4°C, October 7;
Villamontes (Bolivia) max. 47.0°C, October 7;
Pedro Juan Caballero (Paraguay) max. 39.8°C, October 7;
Oeiras (Brazil) max. 43.1°C, October 9;
Providenciales Airport (Turks and Caicos, UK) max. 34.3°C, October 18;
Culiacan Airport (Mexico) max. 44.0°C, October 21;
Maripasoula (French Guiana, France) max. 37.6°C, October 25;
Pangkalapinang (Indonesia) max. 36.3°C, October 26;
Larantuka (Indonesia) max. 38.4°C, October 27; and
Maumere (Indonesia) max. 37.7°C, October 28.
Twenty all-time national/territorial heat records beaten or tied as of the end of October
Cocos Islands (Australia): 32.8°C (91.0°F), February 28, February 29, April 7 (tie);
Costa Rica: 41.0°C (105.8°F) at Cerro Huacalito, March 6; broken again with 41.5°C, March 23, at the same location;
Comoros: 36.2°C (97.2°F) at Hahaya Airport, March 12;
Congo Brazzaville: 39.6°C (103.3°F) at Impfondo, March 13;
Maldives: 35.1°C (95.2°F) at Hanimadhoo, March 24; tied at the same location on April 11;
Togo: 44.0°C (111.2°F) at Mango, March 31;
Mali: 48.5°C (119.3°F) at Kayes, April 3;
Belize: 42.3°C (108.1°F) at Barton Creek, April 10; tied on May 17 at Chaa Creek;
Chad: 48.0°C (118.4°F) at Faya, April 24; tied on June 5 at the same location;
Cambodia: 42.8°C (109.0°F) at Preah Viehar and Svay Leu, April 27;
Laos: 43.7°C (110.7°F) at Tha Ngon, May 1; (3rd time that the previous all-time record was beaten in 2024);
Ghana: 44.6°C (112.3°F) at Navrongo, May 1;
Palau: 35.0°C (95.0°F) at Babelthuap Int. Airport, May 29 (tie); beaten again with (Palau) 35.6°C at Koror on June 2; and
Egypt: 50.9°C (123.6°F) at Assuan, June 7;
Mexico: 52.0°C (125.6°F) at Tepache, June 20 (tie);
Dominican Republic: 41.4°C (106.5°F), at Boca de Mao, August 8;
Colombia: 43.4°C (110.1°F), at Jerusalen, September 14;
Saint Barthelemy (France): 35.8°C (96.4°F) at Gustavia, September 24;
Dominica: 36.6°C (97.9°F) at Canefield; and
Bolivia: 47.0°C (116.6°F) at Villamontes, October 7 (tie).
One hundred seventy-one additional monthly national/territorial heat records beaten or tied as of the end of October
In addition to the 20 all-time national/territorial records set so far in 2024 (plus five nations that tied or broke their all-time record in multiple months), 180 nations or territories have set or tied monthly all-time heat records as of the end of October 2024, for a total of 205 such records:
- January (15): Mayotte, Dominica, Saba, Cocos Islands, Malta, Hong Kong, Ivory Coast, Maldives, Andorra, Portugal, Costa Rica, UK, Seychelles, Martinique, St. Barthelemy
- February (18): Maldives, French Guiana, Guyana, Dominica, Curacao, St. Kitts and Nevis, Antigua and Barbuda, U.S. Virgin Islands, Belize, North Korea, Morocco, French Southern Territories, Hong Kong, Taiwan, Peru, Laos, Chad, Togo
- March (24): Paraguay, Samoa, Zimbabwe, Dominica, Cameroon, Ghana, Guyana, French Guiana, Dominican Republic, Taiwan, Hong Kong, Saba, British Indian Ocean Territories, Solomon Islands, Suriname, Guatemala, Croatia, Poland, Belarus, Lithuania, Latvia, Estonia, Benin, Burkina Faso
- April (28): Dominica, French Southern Territories, Costa Rica, French Polynesia, French Guiana, Guyana, Mauritania, Ivory Coast, Saba, Comoros, British Indian Ocean Territories, Mauritius, China, Slovenia, Croatia, Bosnia, Cape Verde, Nepal, Zimbabwe, Cyprus, Turkey, Niger, Jordan, Israel, Vietnam, Colombia, St. Barthelemy, Laos
- May (20): Sri Lanka, Mauritius, Tuvalu, Ivory Coast, Dominica, Niue, Brazil, Martinique, Maldives, Costa Rica, Mexico, Belize, Cayman Islands, Cuba, Saba, Cocos Islands, Niger, Kuwait, Iraq, St. Eustatius
- June (25): French Southern Territories, Guatemala, Aruba, Curacao, Zimbabwe, Comoros, Grenada, St. Eustatius, North Korea, New Zealand, Dominica, Cocos Islands, Costa Rica, Mauritius, Martinique, Taiwan, Paraguay, Algeria, Turkey, St. Pierre and Miquelon, Kuwait, China, French Guiana, Guadeloupe, Malaysia
- July (16): U.S. Virgin Islands, Palau, Cocos Islands, Aruba, British Indian Ocean Territories, Dominica, Saudi Arabia, Belarus, Mauritius, Maldives, Curacao, Solomon Islands, Northern Marianas, Brunei. Mozambique, French Guiana
- August (11): Palau, French Southern Territories, Australia, British Indian Ocean Territories, Svalbard, Indonesia, Zimbabwe, Eswatini, Ecuador, Comoros, Guadeloupe
- September (14): Taiwan, Slovenia, Sweden, Norway, Mexico, Colombia, North Korea, Hong Kong, Cuba, Bangladesh, Nepal, Cocos Islands, Gabon, Malaysia
- October (9): U.S., Mexico, Saba, Maldives, British Indian Ocean Territories, Brazil, Seychelles, Chile, French Southern Territories
Three monthly national/territorial cold records beaten or tied as of the end of October
China set an all-time cold record for the month of February.
Qatar set an all-time cold record for the month of March.
Myanmar set an all-time cold record for the month of September.
Hemispherical and continental temperature records in 2024
- Highest minimum temperature ever recorded in January in Asia: 28.5°C (83.3°F) at Bangkok Klong Thoey, Thailand, January 14
- Highest minimum temperature ever recorded in February in Asia: 29.1°C (84.1°F) at Diego Garcia (British Indian Territories), February 18
- Highest minimum temperature ever recorded in March in South America: 31.6°C (88.9°F) at Mariscal Estigarribia, Paraguay, March 17
- Highest temperature ever recorded in April in Africa: 48.5°C (119.3°F) at Kayes, Mali, April 3
- Highest temperature ever recorded in May in North America: 51.1°C (124.0°F) at Gallinas, Mexico, May 9
- Highest minimum temperature ever recorded in May in the Southern Hemisphere: 29.7°C (85.5°F) at Funafuti, Tuvalu, May 21
- Highest temperature ever recorded in June in Africa: 50.9°C (123.6°F) at Assuan, Egypt, June 7
- Highest minimum temperature ever recorded in June in the Southern Hemisphere: 29.3°C (84.7°F) at Funafuti, Tuvalu, June 18
- Highest minimum temperature ever recorded in July in the Southern Hemisphere: 28.8°C (83.8°F) at Nukunonu, Tokelau, New Zealand territory, July 16
- Highest minimum temperature ever recorded in August in the Southern Hemisphere: 29.7°C (85.5°F) at Filadelfia, Paraguay, August 3
- Highest temperature ever recorded in August and in all of winter in Oceania: 41.6°C (105.8°F) at Yampi Sound, Australia, August 26
- Highest minimum temperature ever recorded in October in the Southern Hemisphere: 30.9°C (87.6°F) at Cuiaba, Brazil, September 23
- Highest temperature ever recorded in October in North America: 47.2°C (117.0°F) at Palm Springs and Indio, U.S., October 1; and also at Ejido Nuevo Leon, Mexico, October 6
Bob Henson contributed to this post.
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