First Day Of Fall This Year

First Day Of Fall This Year. At a precise moment each september, usually on the 22nd or 23rd, the sun is directly above the equator, marking the autumnal equinox. In the northern hemisphere, the september equinox marks the first day of fall.

When is the first day of fall in 2025? A brief scientific guide to the first day of fall — from the harvest moon to reasons for seasons.