WhenKitStart timer
season directory

Season Countdowns

Track practical reference dates for solstices, equinoxes and seasonal changes.

21DEC
season

Winter

The astronomical start of winter in the Northern Hemisphere, set by the December solstice instant.

Open countdown20MAR
season

Spring

The astronomical start of spring in the Northern Hemisphere, set by the March equinox instant.

Open countdown21JUN
season

Summer

The astronomical start of summer in the Northern Hemisphere, set by the June solstice instant.

Open countdown23SEP
season

Autumn

The astronomical start of autumn in the Northern Hemisphere, set by the September equinox instant.

Open countdown

Using season countdowns

Season countdowns use solstice and equinox reference instants to mark astronomical season changes. Because the event occurs at one global instant, the local calendar date can differ by time zone near midnight.

Meteorological seasons use different fixed month boundaries and are not interchangeable with astronomical seasons. The countdown page identifies the reference used and provides source details for the listed date.

The Northern and Southern Hemispheres use opposite season names for the same solstice or equinox. Check the region shown on the detail page before applying the label to local planning.

Before you make plans

  • Check your local time zone when an equinox or solstice falls near a date boundary.
  • Use meteorological dates instead when a weather or climate source defines seasons that way.
  • Treat seasonal dates as reference points rather than predictions of local weather conditions.