Twilight’s last gleaming
This is such a great time of the year if you enjoy being outdoors after work, since you’ve still got tons of daylight after a 5 p.m. quittin’ time. In Caribou, the latest sunset is at 8:31 p.m. So if you go home, get changed, you have a good three hours of daylight before sundown.
However, it turns out that we still have a pretty good hunk of daylight after sundown! Because usable daylight doesn’t end at sundown, it ends at the end of what is known as civil twilight.
The term “civil twilight” essentially means there is enough light to do things outdoors without needing artificial light. The analogy I like to use is that while you are in civil twilight, you can clearly see the hole while standing on a golf green.
So in actuality, your usable evening light does not end at 8:31 p.m. on the days with the latest sunset (at Caribou this year those dates are June 23 through the 27, 2016, it ends 39 minutes later, at 9:10 p.m. And that latest end of civil twilight time of 9:10 p.m. EDT, holds from June 19th through June 29th this year.
For our family and friends in New Brunswick, due to the fact that they use Atlantic Daylight Time, their usable light does not end until 10:10 p.m. on the dates above. That’s only an hour and fifty minutes before midnight!
Now, you may wonder how long these long, day-lit evenings will last.
Well, by the end of July, civil twilight will end one-half hour earlier, and by the end of August it will end one hour, 26 minutes earlier.
Farmers are usually more concerned with the beginning of civil twilight. At Caribou, the earliest civil twilight is at 3:57 a.m. (again, civil twilight is when there is enough light outside to start doing things outside without needing artificial light)
Incidentally, the times given pertain to sunny days. Cloudy days will of course get light a bit later, and dark a bit earlier.
Oh, and if you are wondering about the flip-side, specifically the latest and earliest civil twilight in late December, the earliest is 6:42 a.m. EST and the latest is 4:28 p.m. EST.
In closing this week, I would like to encourage readers to email me at the address provided at the end of this column with any topics you would like to see covered in future columns. When emailing, please indicate whether you would like your name mentioned in the article, i.e. “John Doe of Linneus asks this week…”, if I write about your topic. Otherwise, I would just write something like “a reader recently inquired …” Either way is totally fine!
Ted Shapiro holds the Broadcast Seal of Approval from both the American Meteorological Society and the National Weather Association. An Alexandria, Va. native, he has been chief meteorologist at WAGM-TV since 2006. Email him at tshapiro@wagmtv.com.
