When Is The First Day Of Fall 2024 California. 3, 2024, at 2 a.m. Sunday marks the beginning of the autumnal equinox but temperatures in southern california will be more summerlike for the first day of fall.

Summer begins with the summer solstice, thursday, june 20, 2024, 4:51 p.m. This year, the first day of fall is sunday, sept.