Weather Tidbits: Astronomical vs Meteorological Seasons
This Weather Tidbits discusses the differences between astronomical and meteorological seasons. Astronomical seasons are based on the Earth’s position relative to the Sun.
It uses solstices & equinoxes; while dates change slightly by year between 89-93 days a season. It also deals with daylight hours in a region. Summer involves receiving more direct sunlight from the sun in the Northern Hemisphere on June 20-22. Winter occurs around December 21-22 where the Northern Hemisphere receives less direct sunlight. The vernal equinox happens on either March 20th or 21st and the autumnal equinox occurring September 22-23. Both of these seasons have the direct sunlight over the equator, with an even amount of daylight.
Meteorological seasons are based on the annual temperature cycle. It follows the calendar meaning more consistency and less range between 90-92 days. This also makes it easier for seasonal statistical calculations. The meteorological seasons are defined with winter or the coldest 3 months starting on December 1st and ending on February 28th or 29th on a leap year. Spring or the 3 warming months is from March 1st to May 31st; followed by summer or the hottest 3 months from June 1st to August 31. Lastly, autumn or the 3 cooling months is from September 1st to November 30th.
Have these set points of when the meteorological seasons start and end at a start and end of a particular month; its easier for meteorologists to look up stats. Compare to astronomically seasons where the seasons change about two-thirds into a month but also the day of when it happens changes from one year to another.