Spring and fall could then neatly occupy the three-month periods in between.
Climatologist Brian Brettschneider created the chart below, which provides a representation of the beginning and end dates for the coldest and warmest three-month periods in 63 U.S. cities. It clearly illustrates the superiority of these “meteorological seasons” for fitting temperature tendencies, in which winter runs from Dec. 1 to Feb. 28, spring Mar. 1 to May 31, summer Jun. 1 to Aug. 31 and fall Sept. 1 to Nov. 30.
(For more on Brettschneider’s methodology, see his blog post: “Defining the Seasons”)
In most cities, the coldest three months much better match Dec. 1 to the end of February than they do Dec. 21-22 to March 20, the dates spanning the conventional definition of winter, based on astronomy.
And the warmest three months much better match June 1 to the end of August than they do June 20-21 to Sept. 22-23.
In other words, if winter is supposed to describe the coldest time of the year and summer the warmest, seasons defined according to weather data do a much better job than seasons defined according to astronomy.
The astronomically defined seasons, based on how the Earth is tilted relative to the sun, are not only out of step with the character of the weather but also confusing because of their variable start and end dates.
Scientists have long recognized the superiority of the meteorological seasons for analyzing data, because their dates are fixed.
It’s past time that, as a nation, we simply adopt these dates for describing the seasons. They are convenient, easy to remember and best fit seasonal nature.