A very interesting
phenomenon related to this: there is a major
holiday near *all* of the season changes (for the
United States, anyway), and one near most of the mid-season markers as well. Something about celebrating
change and all that, I suppose. A great
astronomy professor I once had, Jim Kaler, clued me into this.
Autumnal Equinox:
Labor Day (1st Monday in
September)
Mid-Fall:
Halloween (
October 31st)
Winter Solstice:
Thanksgiving (4th Thursday in
November),
Christmas (
December 25th),
Passover (late
March, early
April),
Kwanzaa (26th-31th of December) and
New Year's Day (January 1st)
Mid-Winter:
Valentine's Day (
February 14th),
President's Day/
Washington's Birthday (3rd Monday in February)
Vernal Equinox:
St. Patrick's Day (
March 17th),
Easter (Early April)
Mid-Spring:
Memorial Day (Last Monday in
May),
Mother's Day (2nd Sunday in May)
Summer Solstice:
Independence Day (
July 4th)
Mid-Summer: ????
Notice that most of the big holidays (including all 3 religious biggies) occur when it is coldest, and relatively few occur in the summertime...I suppose when it's warm, you don't need a special reason to break the monotony and celebrate.