You might wonder why weather scientists ignore the solstice. It all comes down to data consistency and simplicity.
Unlike the astronomical seasons you see on most calendars, meteorological seasons are based on the annual temperature cycle and the Gregorian calendar rather than the Earth's position relative to the sun. Quick Glance: Summer Start Dates Hemisphere Meteorological Start Astronomical Start (Solstice) June 20 or 21 Southern December 1 December 21 or 22 Why Meteorologists Use June 1 when does meteorological summer start