4 seasons?

Today is the Autumn equinox in the Northern hemisphere and an auspicious time to make this post.

I have been wondering, recently, why is "midsummer's day" not in the middle of the summer.

June 21st, is often referred to as the first day of summer, and March 21st as the first day of spring.

This would mean that:-
Summer runs from 21st June to 21st September,
Autumn runs from 21st September to 21st December,
Winter runs from 21st December to 21st March,
Spring runs from 21st March to 21st June.

However, these dates are the solstices, and the equinoxes. To me, this would indicate the middle of the seasons, with, for example, the longest day being in the middle of the summer.

This would mean that:-
Summer runs from 1st May to 31st July,
Autumn runs from 1st August to 31st October,
Winter runs from 1st November to 31st January,
Spring runs from 1st February to 31st April.
(approximately)

Well, thank heavens for Wikipedia, again. In the article on The Seasons , All is revealed. There are several conventions for defining the Seasons, and, it seems that the British Traditional reckoning holds closest to my version, above, as does the Celtic Calendar:-

"In the United Kingdom, the seasons are traditionally considered to begin about seven weeks earlier: spring begins on Candlemas, summer on May Day, autumn on Lammas, and winter on All Hallows. The Irish calendar (celtic) uses almost the same reckoning; Spring begins on February 1 / Imbolc, Summer on May 1 / Beltane, Autumn on August 1 / Lughnasadh and Winter on November 1 / Samhain. "

Old wisdom proves its worth again?