The term “season” can refer to different timing schemes, so the exact dates depend on which system you want to use.

• Astronomical seasons (based on equinoxes and solstices)
  • Spring begins at the vernal (spring) equinox
  • Summer begins at the summer solstice
  • Autumn (fall) begins at the autumnal equinox
  • Winter begins at the winter solstice
  • The calendar dates shift slightly year to year (usually around March 20–21, June 20–21, September 22–23, and December 21–22). If you need the precise times for a given year or your city, I can provide them.
• Meteorological seasons (three-month blocks)
  • Spring: March 1 to May 31
  • Summer: June 1 to August 31
  • Autumn (Fall): September 1 to November 30
  • Winter: December 1 to February 28 (or 29 in a leap year)
  • These are fixed, making it easier for planning and statistics, but they don’t align exactly with the Sun’s positions.

If you’re asking about a specific region (e.g., the United States, Europe) or a particular year, I can give you the exact start and end dates for that context. Please tell me which system you prefer (astronomical or meteorological) and the location and year of interest.