Happy First Day of (Astronomical) Winter

Bill’s Blog

Posted: Dec 22, 2019 / 02:57 AM EST Updated: Dec 22, 2019 / 03:03 AM EST


Yesterday (Sat.) was the Winter Solstice. It occurred at 11:19 pm. At that minute, the sun was as far south as it gets during its yearly journey. Today (Sun.), we get more daylight than yesterday, but the difference is less than one second. Right now, the sun climbs to an altitude of just 23.7 degrees above the southern horizon at solar noon, which is at 12:41 pm. We live at the west edge of the (Eastern) time zone, so our sunrise and sunset come a little later in the day than the eastern edge of the time zone (Boston, New York).

While it’s the Winter Solstice in the Northern Hemisphere, it’s the Summer Solstice in the Southern Hemisphere.  Today, the sun is directly overhead at solar noon over an imaginary line called the Tropic of Capricorn, which is 23.4368 deg. south of the Equator.  The daylight (sunrise to sunset) is 9 hours and 31 seconds in Grand Rapids, Michigan today.     On the Summer Solstice (June 21 or 22), the sun climbs to 70.5 deg. above the horizon and we get 6 hours and 21 minutes more daylight in Grand Rapids on the Summer Solstice than at the Winter Solstice.

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Path of the sun in Fairbanks, Alaska on the Winter Solstice

This is what the sun looks like today in Fairbanks, Alaska.  You’ve got to have a clear horizon to the south to see any sunshine at all, because the sun climbs to only 2 deg. above the horizon at solar noon.  The official sunrise today in Fairbanks is 10:58 am and the sunset is at 2:40 pm.  North of the Arctic Circle, there is no sunshine today.  At Barrow AK, they won’t see the sun until January 23rd.

I just drove up from Oak Ridge TN – Oak Ridge is farther south and daylight is 42 minutes longer than in Grand Rapids. The sun climbs to 31 deg. at solar noon in Oak Ridge.

At Miami FL, they get 10 hours and 32 minutes of daylight today and the sun climbs to an angle of 41 degrees above the southern horizon at solar noon.

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Temperatures lag the position of the sun by about one month…so, on average the coldest temperatures in the Northern Hemisphere don’t come on the Winter Solstice, but around one month from now in mid-late January.