When Is Summer 2024 Date. When is the first day of summer in 2024? The summer solstice is the longest day of the year , when the sun is at its highest point.
The summer solstice is the longest day of the year , when the sun is at its highest point. Solstice—the longest day of the year in the northern hemisphere and the shortest in the southern hemisphere—will occur on thursday, june 20, at 20:50.