Two areas of continental U.S. entering their darkest days

 

Rough approximation of areas of the continental U.S. seeing sunsets before 4 p.m.  in the fall and winter.

 

On Friday, November 20, the sun set in Bonners Ferry at 3:59 p.m. and North Idaho and a sliver of northeast Washington became the first places in the contiguous United States to see darkness fall before 4 p.m. in the year 2020. On Monday, November 23, the sun set at 3:59 p.m. in northern Maine.

They are the only places in the lower 48 to see the sun set before 4 p.m. in late fall and early winter thanks to their northerly latitudes and easterly positions within their time zones.

The winter solstice, the shortest day of the year, falls at 8:28 a.m. Monday, December 21, the first day of winter, when the sun on our sky’s dome reaches its farthest southward point for the year, after which the days will once again begin to lengthen.

On that day, sunrise in Bonners Ferry is at 7:35 a.m., sunset at 3:51 p.m. There will be 11.52 hours of darkness, 1:17 hours of astronomical twilight, 1:21 hours of nautical twilight and 1:14 hours of civil twilight. The remaining day will be 8:16:17 hours long. December 20 will enjoy 8:16:18 hours and December 22 will see 8:16:23 hours of daylight.

In Bonners Ferry, the earliest sunsets will be December 5 through 16, with sunset arriving at 3:49 p.m. The latest sunrises arrive at 7:38 a.m. on the last two days of the month, December 30 and 31.

The latest sunrise and earliest sunset don’t converge on the solstice because the Earth’s orbit around the sun isn’t a circle, but an ellipse.

On January 1, sunset will again come at 4 p.m. and each day until this time next year sunrise will come after 4 p.m., reaching the longest day of the year in June.

And you might not know it, but in mid-June when days here are at their longest, there are a few days with no night at all.

On June 14 there is a mere 20 minutes of actual night, on June 27 seven minutes. From June 15 to June 26, we never leave astronomical twilight, when the sun is between 12 and 18 degrees below the horizon.

www.timeanddate.com/sun
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