First Day Of Summer 2024 Date. Summer begins with the solstice on thursday, june 20, 2024, marking the astronomical first day of summer in the northern hemisphere. 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.

Summer 2024 starts on thursday, june 20th in the northern hemisphere, with the first day of summer being the longest daylight day of the year with the earth’s axis having reached its furthest tilt and begins to change directiion back. (in the southern hemisphere, it is around december 21 or 22.) this date is considered to be the first day of summer.