First Day Of Autumn 2025. What is the exact time of the start of fall in 2025? Summer begins with the summer solstice, friday, june 20, 2025, 10:42 p.m.
The september or autumnal equinox is when the sun crosses the celestial equator, moving from north to south. The autumnal equinox, or the first day of fall in the northern hemisphere takes place every year on september 22nd or september 23rd.