June 2023 Was Earth's Record Hottest June, NOAA And NASA Find

 Jonathan Erdman

Published: July 13, 2023

Earth just sweltered through its record hottest June and 2023 could become the planet's warmest year, according to newly released data from multiple agencies.

J​une's globally averaged surface temperatures — including those over both land and ocean — were warmer than any year since 1850, according to data from NOAA released Thursday.

T​his topped the previous record warm June in 2020 and was the first time the June departure from average was over 1 degree Celsius in NOAA's 174-year database.

Global June temperature departures from average from 1850 through 2023. These are relative to the 20th-century average (1901-2000).

These findings matched other data from Berkeley Earth, NASA's Global Institute for Space Studies and the European Centre for Medium-Range Weather Forecasts (ECMWF).

A​ll eight of the planet's hottest Junes have occurred since 2015, according to NOAA. It was also the 532nd consecutive month the planet's temperatures were at least slightly above average. The last cooler than average month was February 1979, NOAA's data shows.

O​ceans drove the record warm June. Sea surface temperatures over the planet's oceans were by far the warmest of any June in records since the mid-19th century. In fact, the ocean warmth was the most above average of any single month since 1850, according to NOAA.

One factor contributing to this record warmth was an intensifying El Niño, the periodic warming of a strip of the equatorial Pacific Ocean.

A​nother was the exceptional, widespread warmth in the eastern and tropical North Atlantic Ocean. Weaker than usual subtropical high pressure led to lighter trade winds that didn't allow the usual cooler water to upwell – or move up – to the surface in the tropical North Atlantic Basin.

There was also a lack of typical exhalations of dust-laden air from the Sahara Desert westward over the tropical Atlantic in June. Less airborne dust to reflect the sun's energy would also contribute to warmer than average water in the tropical North Atlantic.

A​s the graph below shows, since late April, a section of the eastern North Atlantic Ocean has been record warm for that time of year than any previous year since 1979.

Daily sea surface temperature anomaly (degrees Celsius) averaged over the eastern North Atlantic Ocean in 2023 (black line) compared to other years since 1979.

T​hose weren't the only exceptionally warm areas of the ocean.

A​ccording to an analysis from Alaska-based climatologist Brian Brettschneider, stretches of the North Atlantic near western Europe, the South Pacific near New Zealand and the Indian and Southern oceans were also record warm in June.

T​his was the third straight month global ocean surface temperatures were record warm, according to NOAA.

S​everal countries had their record hottest June. Among these included the United Kingdom, Ireland, Belgium and the Netherlands. The U.K. topped its previous hottest June, in records dating to 1884, by about 1.6 degrees Fahrenheit. In the realm of national temperature data compiled from numerous observing stations over a month's time, that's a pummeling of a previous record.

C​anada also sweltered through a record hot June, which followed their record hot May, according to Brettschneider. That's one driver of the country's most widespread wildfire years in modern times.

T​he Caribbean region also had its hottest June, according to NOAA. San Juan, Puerto Rico, had by far its hottest month in records dating to 1956.

C​hina, France and Japan narrowly missed their record hottest Junes.

T​he past two Junes are now the two hottest on record in China. France fell just shy of their hottest June from 2003, the summer in which heat waves claimed an estimated 15,000 lives in the country, and at least 70,000 in Europe.

W​ill 2023 be the planet's hottest year? NOAA's calculations suggested based on the current pace, there was a 20 percent chance 2023 could end up as the planet's warmest year on record.

J​anuary through June temperatures were third warmest in NOAA's data, behind only 2016 and 2020.

N​ot all agree the chance of a record warm year is that low.

B​erkeley Earth considered that chance "likely" based on their analysis released Tuesday.

Year-to-date global temperature anomalies (above the 1901-2000 average) for 2023-to-date (black line), compared to the planet's 10 warmest years.

U​ltimately, whether a month or year is slightly warmer than another year isn't as important as the longer-term trend of planetary warming since 1980.

M​ORE ON WEATHER.COM:

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Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on Twitter and Facebook.

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.

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.