If you ask five different people when the seasons start and end, you might get five different answers. Some swear by the solstices and equinoxes, looking to the stars for the definitive "first day." Others argue that March 1st is the obvious start of spring, as it aligns with the rhythm of the temperature charts. Surprisingly, both are correct.
National Centers for Environmental Information (NCEI) (.gov) Seasonal Breakdown for 2026 The dates below apply to the Northern Hemisphere
Occur in summer and winter when the Earth's tilt reaches its maximum angle toward or away from the Sun, resulting in the longest and shortest days of the year. when do the four seasons start and end
September, October, and November represent the transition from summer heat to winter cold. September 1 is the logical start of the cooling trend.
Seasons of the Year: When Do They Start and End? - Time and Date If you ask five different people when the
Meteorologists and climatologists break the seasons down into consistent, three-month groupings based on annual temperature cycles and the Gregorian calendar. This fixed structure allows scientists to easily track climate statistics, calculate monthly averages, and compare seasonal weather data from year to year. Northern Hemisphere Meteorological Schedule
Understanding why these two systems coexist helps clear up confusion when looking at calendars or weather forecasts. Astronomical Seasons Meteorological Seasons Earth's physical position relative to the sun Annual temperature cycles and calendar months Start/End Dates Variable (shifts slightly due to leap years) Fixed (always starts on the 1st of a month) Length Varies between 89 and 93 days Always exactly three full calendar months Primary Use Astronomy, navigation, traditional calendars Climate science, weather forecasting, agriculture Other Seasonal Systems Around the Globe National Centers for Environmental Information (NCEI) (
Starts March 1 (Meteorological) or the March Equinox (Astronomical).
The same applies to winter. The shortest day of the year is in December, but the deepest, coldest winter weather usually holds off until January and February because the planet is still slowly losing the heat it stored during the autumn.