The June-July-August season was the warmest on record globally by a large margin. The European Union’s Copernicus Climate Change Service (C3S) reports that the average global temperature spiked to 16.77°C during this period, 0.66°C above the 1940-2023 average. The agency also reported that last month was the hottest August on record globally.

This boreal summer season registered record-breaking high sea surface temperature anomalies in the North Atlantic and for the global ocean, Copernicus said in its report. There were marine heatwaves in several areas around Europe, first around Ireland and the United Kingdom in June and then across the Mediterranean in July and August.

The three-month period also saw above-average precipitation over most of Western Europe and Turkey, breaking local rainfall records. Flooding occurred as a result in many European regions, but also in parts of Asia, Chile, Brazil, Australia, and the US. In contrast, Iceland, Canada, Central Europe, and most of South America experienced drier-than-average conditions.

Many cities in the southern US broke records for their hottest June-through-August periods, as Axios reported. This includes New Orleans, Houston, Miami, and Phoenix. Other municipalities experienced a top-10-warmest meteorological summer, such as Dallas and Austin. In South America, all-time winter heat records were set from Brazil to Argentina.

“Global temperature records continue to tumble in 2023, with the warmest August following on from the warmest July and June leading to the warmest boreal summer in our data record going back to 1940,” Samantha Burgess, deputy director of Copernicus, said in a media statement. “2023 is currently ranked as the second warmest.”

August’s worrying numbers

Last month was the warmest August on record globally, and warmer than all other months this year except July, Copernicus said in its report. The global average surface air temperature of 16.82 degrees Celsius was 0.71C warmer than the 1991-2020 average for August, and 0.31C warmer than the previous hottest August in 2016.

August is also estimated to have been around 1.5C warmer than the preindustrial average for the 1850-1990 period. Countries have committed to the Paris Agreement on climate change to limit the global temperature increase to 1.5C. Heatwaves occurred in multiple regions of the Northern Hemisphere, including parts of the US and Europe.

Global average sea surface temperature increased in August after a long period of unusually high temperatures since April. Every day from July 31st to August 31st has broken global average sea surface records — it’s this bad.

As a whole, August saw the highest global monthly average sea surface temperatures on record across all months (20.98C).

Overall, the temperature variation for the first eight months of the year (January-August) ranks second-warmest on record – only 0.001C below 2016, currently the warmest year on record. A report earlier this year predicted that there’s a 98% likelihood that at least one of the next five years will be the warmest on record.

“Our planet has just endured a season of simmering — the hottest summer on record. Surging temperatures demand a surge in action. Leaders must turn up the heat now for climate solutions. We can still avoid the worst of climate chaos – and we don’t have a moment to lose,” UN Secretary-General António Guterres said in a news release.