When Is Autumn Equinox 2024 Uk. Autumn equinox 2024 occurs sunday 22 september at 12:44pm (13:44 utc), as this is when the centre of the sun crosses the celestial equator. According to the astronomical autumn, the autumn equinox will signal the start of the season which starts on the 22nd of september 2024.
When is the first day of fall 2024? Autumnal equinox marks the end of summer and the beginning of fall.