June 2023 was hottest ever

This June was the hottest on record, according to data from the European Union’s Copernicus Climate Change Service.

Global temperatures during the last month were 1 degree Fahrenheit above the 1991-2020 average for the month, breaking the previous record of 0.7 degrees above average set in 2019. The last nine Junes are all among the hottest ever recorded.

Regionally, much of northwestern Europe also saw record temperatures, while parts of North America, Asia and eastern Australia saw temperatures considerably above average. Meanwhile, the western U.S., western Russia and western Australia saw cooler temperatures than average during the month. Much of the North American continent also saw drier temperatures than average, setting the stage for devastating wildfires in both the U.S. and Canada. The blazes in Canada also resulted in smoke that drifted south and blanketed much of the eastern U.S. in haze last month.

The month also saw the highest sea surface temperatures of any recorded June, with particularly warm north Atlantic temperatures. The Baltic Sea and coastal waters around Ireland and the U.K. also saw marine heatwaves during the month, reaching category 4, or “extreme,” according to the service.

The marine temperatures in particular are likely due to a combination of climate change and shorter-term trends that have altered atmospheric circulation, according to Copernicus. The oceans have taken up more than 90 percent of the extra warmth generated by climate change and are set to comprise up to quadruple the heat they did from 1970 to 2019 by the end of the century, according to the United Nations’s Intergovernmental Panel on Climate Change.

The Copernicus analysis is the latest indicator of record-breaking heat this year. Earlier this week, Monday was the single hottest day on record, only for the record to be broken the following day.