August shares record for world's hottest month ever as sea temperatures reach all-time high

A wildfire burns in a forest in the Gironde department of France in July. For Western Europe, this summer was the warmest on record, surpassing the previous record, which was set in 2003. File picture: Reuters/Stephane Mahe

August was the world’s joint hottest month on record, tied with July 2023 and also saw the average sea surface temperature reach a record high.

The latest Copernicus report said the global surface air temperature was 1.65°C higher than the estimated pre-industrial baseline. It was the first month since November 2025 to exceed 1.5°C.

The period from June to August 2026 was the joint warmest on record globally, on par with 2024.

In Europe, the average temperature over land in August 2026 was 20.26°C, 1.1°C above the 1991-2020 average for the month. This makes it the fourth-warmest August on record on the continent.

Additionally, this summer was the third warmest on record for Europe, behind 2024 and 2022. However, for Western Europe, it was the warmest summer on record, surpassing the previous record, which was set in 2003.

The region also saw further heatwaves in August, which continued an “exceptional run of extreme heat that began in May". France, the UK, Hungary, Romania and Serbia also saw severe drought conditions during the month, with the Rhine, Danube, Southern Bug and the Dnieper rivers also facing “exceptionally low” river flows.

Looking at sea temperatures, August also saw the joint highest monthly average tied with March 2024, at 21.11°C.

The report said record high sea surface temperatures were seen across the tropical Pacific, an area where “a potentially extreme El Niño event continues to intensify". 

“The impacts of this event are already being felt over land, with conditions favouring the intensification of seasonal wildfires across Indonesia,” the report said. It said El Niño conditions will continue to further strengthen in the coming months.

Around Europe, sea surface temperatures reached record highs for August along the Atlantic coast and in the western Mediterranean, which Copernicus says is associated with widespread strong or severe marine heatwave conditions.

Samantha Burgess, strategic lead for climate at the European Centre for Medium-Range Weather Forecasts, said August was a remarkable month in the global climate record.

She said:
It was both the warmest August and the warmest month ever recorded, with global temperatures reaching 1.65°C above pre-industrial levels, marking the return of global temperatures above 1.5°C.

“Combined with record global sea surface temperatures and the warmest summer on record for Western Europe, these observations show how climate change is driving extremes across both the atmosphere and the oceans. The impacts of these conditions are increasingly being felt by communities, economies and ecosystems across the world,” Ms Burgess added.

It comes as Ireland records the hottest summer in 127 years. The average temperature for June, July, and August was 16.28°C, making it 0.09°C warmer than the previous record set in 2025, according to Met Éireann.

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The national forecaster described the summer as “exceptionally warm relative to climatological norms”, with temperatures 2.03°C above the 1961-1990 average.

Six of Ireland’s hottest summers have now occurred since 2001, highlighting the recent trend towards warmer conditions.