When does autumn start?

Autumn, also called fall, begins on the autumnal equinox — the moment when the Sun crosses the celestial equator heading toward the opposite hemisphere. In the Northern Hemisphere this falls around September 22–23, while in the Southern Hemisphere autumn starts around March 20. Like the vernal equinox, day and night are approximately equal in length on this date.

The season is defined by gradually shortening days, cooling temperatures, and the dramatic color change of deciduous leaves. Many harvest festivals worldwide are timed to the equinox, celebrating the end of the growing season and the transition into winter.

Tool description

This tool shows a live countdown to the next autumn equinox. It updates every second and displays the remaining days, hours, minutes, and seconds. A hemisphere selector lets you choose between Northern and Southern Hemisphere dates, and a progress bar tracks how far through the year you are toward the start of autumn.

Features

  • Live countdown refreshing every second with days, hours, minutes, and seconds
  • Hemisphere toggle between Northern (September 22) and Southern (March 20) autumn dates
  • Progress bar visualizing the percentage of time elapsed since the previous autumn ended
  • Automatic detection when autumn is currently in season
  • Localized target date display based on your browser settings

Use cases

  • Planning harvest events, leaf-peeping trips, or fall photography sessions around the equinox
  • Counting down to the start of a new school or academic year in regions where terms begin in autumn
  • Learning when astronomical autumn starts in different parts of the world