Astronomical seasons are defined by the Earth’s tilt and its orbit around the sun. In the Northern Hemisphere, these dates generally fall around the 20th–22nd of the month. Starts: Typically around March 20–21 .
| Season | Astronomical Start | Meteorological Start | | :--- | :--- | :--- | | | September 22 (Vernal Equinox) | September 1 | | Summer | December 21 (Summer Solstice) | December 1 | | Autumn | March 20 (Autumnal Equinox) | March 1 | | Winter | June 21 (Winter Solstice) | June 1 | when do the four seasons start and end
You’ll notice that the astronomical dates are not fixed (e.g., “June 20 or 21”). This fluctuation occurs because a tropical year (the time it takes Earth to orbit the sun) is actually about 365.2422 days long. To correct for this, we add a leap day every four years, which shifts the precise moment of the equinoxes and solstices slightly. Astronomical seasons are defined by the Earth’s tilt
Here is the exact breakdown of the seasons for both systems in the . (Note: If you live in the Southern Hemisphere, the seasons are exactly reversed). | Season | Astronomical Start | Meteorological Start
August 31, 2026 (Meteorological) / September 21, 2026 (Astronomical)
To solve this,
. These dates vary slightly each year because Earth's orbit is not a perfect 365 days. Royal Meteorological Society