The team at AEM's Davis Instruments brand recently published a breakdown of the incredible early summer heat wave that moved across eastern North America and western Europe between June 23 and June 26, 2025. Their article highlights some of the most striking temperature records that fell across the U.S. and world while providing context for a week that's redefined the idea of a hot June.
Here's a preview of that piece, which you can read in its entirety on the Davis Instruments site.
The summer solstice was on June 20th this year, and it didn’t take long for the feeling to set in. For many places around the globe, June 23-26 brought a heat wave that rewrote the record book for early summer temperatures.
In the United States alone, more than 280 locations set new temperature records, and 121 more tied their all-time highs during that span. Most of the new records in the U.S. were set in the northeast. At Davis headquarters in Hayward, California, on the west coast, the high temperature for the 24th was a comfortable 64 °F (17.8 °C)— a little cooler than usual, actually.
In New York City, however, temperatures in Central Park hit a record-setting 98 °F (36.7 °C) that day, toppling a mark that had stood since the early summer of 1888 and besting the daily average high by more than 16 degrees Fahrenheit. According to NOAA, it was NYC’s hottest day since 2012.
Nearby, in Mill Basin, Brooklyn, a Davis WeatherLink user captured a punishing reading of over 107 °F (41.6 °C).
Boston set a June temperature record for the entire New England region on the 24th, hitting 102 °F (38.9 °C). Roughly 30 miles northeast, in Lowell, Massachusetts, temperatures reached 99 °F (37.2 °C), breaking the record of 95 °F (35 °C) set in 1957. Even further north, Pinkham Notch, New Hampshire—elevation 2,032ft (619 m)—hit 89 °F (31.7 °C), breaking a record that stood since 1975.
In fact, arguably all the New England states (Connecticut, Rhode Island, Vermont, New Hampshire, Massachusetts, and Maine) experienced or equaled their hottest June days on record in 2025.
It wasn’t just northerners who were treated to the excruciating heat, however. A weather station in Baltimore’s Inner Harbor registered an incredible 104 °F (40 °C), missing the city’s record, which was set in 2012, by a single degree.
...Continue here to get the rest of the story, including:
- Additional details about how heat disrupted life in the American South and Midwest
- More record-setting temperatures from across Canada & Europe
- Details on the backdoor cold front that brought relief (and what's next)