21 December 2021
By the time the winter solstice arrives today at 10:59am we already will have gained three minutes at the end of the day.
Though the winter solstice has the shortest daylight — only 9 hours, 16 minutes and 57 seconds in Pittsburgh — it doesn’t have the earliest sunset nor the latest sunrise. That’s because the length of the solar day varies, solar noon to solar noon, while our clocks use the average day length of 24 hours. For a host of reasons, our clocks do not match solar time(*).
Thus the earliest sunset occurred 1 to 13 December in Pittsburgh and the latest sunrise won’t happen until 31 December and will linger for more than a week. See table below, built from information at timeanddate.com.Pittsburgh PA Sunrise & Sunset near the Winter Solstice
|1 Dec 2021 (earliest sunset) to 13 Dec 2021||7:24 am to 7:34 am||4:53 pm (earliest sunset)|
|21 Dec 2021 (winter solstice)||7:39 am ET||4:56 pm ET|
|31 Dec 2021 (latest sunrise) to 8 Jan 2022||7:43 am (latest sunrise)||5:03 pm to 5:10 pm|
If you cue on sunrise the days will seem to get shorter into early January.
If you cue on sunset your day has already gained three minutes this month and is getting longer.
(*) For the ultimate in “Our clocks don’t match solar time” consider that Solar Noon happens around 1pm during Daylight Saving Time. Solar Noon is in the 12 o’clock hour, as it should be, during Standard Time.
(photo by Kate St. John)