Extreme Temperature Diary- Thursday September 14th, 2023/Main Topic: Earth Sees Its Hottest August in Recorded History

The main purpose of this ongoing blog will be to track planetary extreme, or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to Main Topic: Libya Ravaged by Extreme Flood Waters Leaving 5000+ Dead or record temperatures as ETs (not extraterrestrials).😉

Main Topic: Earth Sees Its Hottest August in Recorded History

Dear Diary. Our globe continues to warm due to carbon pollution, now at an increasingly higher rate this year. The climate crisis is deepening due to each tick of additional warmth year after year, with the latest alarming item being a medicane named Daniel that killed thousands in Libya from unprecedented flooding. For today’s main subject here is a repost of most of Dr. Jeff Master’s report on the fact that August and the Northern Hemisphere summer months of June through August were the hottest in recorded human history. All of this is really bad news:

August 2023 was Earth’s hottest August on record » Yale Climate Connections

August 2023 was Earth’s hottest August on record

The year 2023 is at least 93% likely to be the planet’s hottest year on record.

Jeff Masters


Members of the Hays County Emergency Service Districts and the Kyle and Buda Fire Departments rest together while combatting a wildfire during an excessive heat warning on August 8, 2023, in Hays County, Texas. (Image credit: Brandon Bell/Getty Images)

August 2023 smashed the record for hottest August in Earth’s history, spiking to a remarkable 1.25 degrees Celsius (2.25°F) above the 20th-century average, NOAA’s National Centers for Environmental Information reported September 14. NASABerkeley Earth, the Japan Meteorological Agency, and the European Copernicus Climate Change Service also rated August 2023 as the warmest August on record, crushing the previous August record by a huge margin. Global temperature analyses extend back to 1850 in the NOAA database.

Figure 1. Departure of temperature from average for August 2023, the hottest August for the globe since record-keeping began in 1850. Record-warm temperatures covered nearly 13% of the world’s surface. (Image credit: NOAA/NCEI)

Land and ocean areas each had their warmest August on record in 2023, and August was the fifth consecutive month with record-high global ocean temperatures, which have been unusually extreme (see Tweet below).

North America, Asia, Africa, and South America each had their warmest August on record; Europe, and Oceania each had their second-warmest August. August broke the record in South America for greatest monthly departure of temperature from average for any month: +2.4 degrees Celsius (+4.32°F). As reported in our post on Monday, August ranked as the ninth-warmest August on record in the United States.


Earth has its hottest three-month period on record

The period June-August 2023 (summer in the Northern Hemisphere) was the hottest on record globally by a huge margin, according to NOAA. Because most of Earth’s land area is in the Northern Hemisphere, the June-August period is normally the planet’s warmest three months of the year for surface temperature; thus, June-August 2023 also ranks as the warmest of any three-month period in more than a century of record-keeping.

Asia, Africa, North America, South America and Oceania had their warmest June-August periods on record; Europe had its third-warmest summer on record, and the contiguous U.S. had its 15th-warmest summer on record.


According to an analysis by Climate Central, 3.9 billion people across the world suffered extreme temperatures made at least three times more likely by climate change for over 30 days during the June-August period; 1.5 billion people experienced extreme temperatures at this level for all 92 days of the June-August period. About 98% of the global population was exposed to extreme heat made at least two times more likely by human-caused global warming during this period.

2023 now very likely to be Earth’s warmest year on record

The year-to-date period of January-August is the second-warmest on record globally. And according to NOAA’s latest Global Annual Temperature Rankings Outlook and the statistical model it uses, there’s a 93% chance of 2023 being the warmest year on record. Note that this NOAA outlook is based purely on statistical comparison to past temperature trends and uses no forward-looking weather or climate model guidance, so it may still be an underestimate. Climate scientist Zeke Hausfather (see Tweet below) says 2023 is virtually certain to be the warmest year on record.


Using NASA data, summer 2023 was 1.4°C above the temperature of the 1880-1899 period, which is commonly called “preindustrial” (the difference between the 1951-1980 baseline reported on the NASA website and the 1880-1899 period is 0.226°C). Hausfather gives roughly a 50% chance 2023 will be at least 1.5 degrees Celsius above preindustrial temperatures. This is the target threshold for the stabilization of the long-term climate agreed upon in international climate negotiations. This year’s exceedance would very likely be just a temporary breach of the 1.5°C threshold, but the planet may start regularly exceeding this mark by the 2030s, especially if major emission cuts are not implemented by then.


El Niño intensifies to the “strong” category

El Niño conditions strengthened over the past month in the eastern tropical Pacific and have surpassed the “strong” threshold, according to NOAA’s September 14 discussion. Sea surface temperatures in the Niño-3.4 region were 1.6 degrees Celsius above average over the past week; a “strong” El Niño event is defined when these sea surface temperatures are in excess of 1.5 degrees Celsius above average. NOAA gave a 71% chance of the current event being defined as a strong El Niño for the November-January period and a 95% chance that El Niño conditions would continue through March 2024.

Arctic sea ice: eighth-lowest August extent on record

Arctic sea ice extent during August 2023 was the eighth-lowest in the 45-year satellite record, according to the National Snow and Ice Data Center. The shipping channels through the southern route of the Northwest Passage through Canadian waters opened to ice-free navigation during August. The Northeast Passage (or Northern Sea Route) along the northern coast of Russia was also open to ice-free navigation. The northern route of the Northwest Passage had the lowest ice coverage of any year except for the record-low year of 2011 but remained closed to ice-free navigation during August. The Arctic had its warmest August on record, according to NOAA.

Antarctic sea ice: lowest on record

Antarctic sea ice extent in August was by far the lowest on record, the fourth-consecutive month with a record low. However, ice growth during the month increased at a faster-than-average pace during the month over portions of the Antarctic waters.

Figure 3. Melt extent in Greenland through August of 2023 (red line) compared to average (blue dashed line). (Image credit: National Snow and Ice Data Center)

Greenland: second-largest melt year on record

An unusual late-summer melting event in Greenland during August caused widespread melting on the Greenland ice sheet and was the largest melt event on record so late in the year. According to the National Snow and Ice Data Center, the extent of surface melt as of the end of August 2023 was the second-largest in the 45-year satellite record, trailing only the extreme melt year of 2012.

Notable global heat and cold marks for August 2023

The information below is courtesy of Maximiliano Herrera. Follow him on Twitter: @extremetemps

  • Hottest temperature in the Northern Hemisphere: 52.5°C (126.5°F) at Kanaquin, Iraq, August 11;
  • Coldest temperature in the Northern Hemisphere: -26.8°C (-16.2°F) at Summit, Greenland, August 19;
  • Hottest temperature in the Southern Hemisphere: 45.0°C (113.0°F) at Villamontes, Bolivia, August 21; and
  • Coldest temperature in the Southern Hemisphere: -82.0°C (-115.6°F) at Vostok, Antarctica, August 6.

Major weather stations in August: 228 all-time heat records, no all-time cold records

For this complete long list see:

August 2023 was Earth’s hottest August on record » Yale Climate Connections

Bob Henson contributed to this post.

Here is more climate and weather news from Thursday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)

*Due to technical difficulties, there are no other added items to today’s post.*

If you like these posts and my work on record temperature ratios, please contribute via my PayPal widget on this site. Thanks in advance for any support. 

Guy Walton… “The Climate Guy”

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