The first day of summer is marked by the summer solstice, or the longest day of the year. Here's what to know about summer 2025.

The summer solstice on 21 June marks the longest day of 2024 in the Northern Hemisphere. While many believe this signals the peak of summer heat, science says otherwise. The sun reaches its highest point,

The 2025 summer solstice falls on Friday, June 20, at 10:42 p.m. ET, according to NASA and the Old Farmer's Almanac. This marks the longest day of the year in the northern hemisphere, when the Earth's tilt positions it closest to the Sun.