Astronomical Seasons

We experience seasons because of the earth's orbit around the sun and its tilt. The exact times when seasons officially change are determined by the timing of the equinoxes and solstices. For more information read about astronomical seasons at the National Weather Service.

When tracking outdoor activities seasonally, sponsoring organizations such as the Appalachian Mountain Club require that hiking activities both start and end within the season for the activity to be counted. List Hiker automatically checks your activities to ensure that they comply with rules for counting seasonal activities.

To help you plan your activities, the table below shows the exact times when seasons change each year, in your local timezone.