Boston has declared a heat emergency from Sunday, June 22 through Tuesday, June 24 due to a forecast calling for extremely hot weather.

2024 highlights: Our hottest reading was 98 degrees on June 19. There were two heat waves last summer: June 18–20 and July 15 ...

It will be the hottest weather of the year in most of Massachusetts Thursday and the first time Boston has hit 90 in 2025.