First Day Of Summer 2025. Est sunday, march 10, for spring forward and ended, or fell back to standard time, at 2 a.m. In the southern hemisphere, it will occur on december 21, 2024.
(in the southern hemisphere, it is around december 21 or 22.) this date is considered to be the first. Find out the date when summer is in 2025 and count down the days until summer with a countdown timer.