When Is Fall 2025 In Canada Usa. Fall officially begins on sunday, september 22, 2025, at 8:44 a.m. Winter starts at the moment when the sun is farthest south:
Autumn / fall equinox 2025 the autumn or fall equinox signals the end of summer on the astronomical calendar. Fall starts at the moment when the sun is directly over the equator, going from north to south: