Autumn Equinox 2025 Australia Date. Fall equinox, harvest home, feast of avalon origins and significance: At the summer solstice, we have the longest day and the shortest night of the year.

When is the first day of autumn in australia? The occurrence of spring equinox usually falls on the 20th or 21st march, and the autumnal equinox falls on 22nd or 23rd september every year.