Happy Winter Solstice, more commonly known as the First Day of Winter!

This year, the Winter Solstice takes place at 10:59am ET on Tuesday, December 21.

The Winter Solstice occurs when the Northern Hemisphere is at its furthest tilt away from the sun during Earth’s orbit.

As a result, the sun’s rays hit the Earth’s surface at a greater angle in the Northern Hemisphere, resulting in shorter hours of daylight as well as less solar radiation. This is in contrast to the Equator, where the sun’s light hits the Earth’s surface nearly straight on overhead.

Science Behind Winter Solstice (Source: NASA)

In North Georgia, the amount of daylight on the First Day of Winter is approximately 9 hours and 54 minutes, but on each day thereafter, daylight will increase until the Summer Solstice (as much as 14 hours and 23 minutes on the Longest Day).

The shortest day of the year is the Winter Solstice (December 21st). This map shows the amount of daylight (not sunshine) on that day. pic.twitter.com/Xlz0LHgv4M
— Brian Brettschneider (@Climatologist49) December 10, 2017

First Day of Winter in Atlanta: What to Expect

The Winter Solstice lands on Tuesday, December 21 this year, and the average daytime high in Atlanta on this date is 55 degrees; the average morning low is 38 degrees.

The warmest daytime high on December 21 occurred in 1998, when thermometers reached 73 degrees. The coldest morning low occurred on this date in 1901, when thermometers dropped to 6 degrees.

This year, Winter will start off on trend with temperatures at or below average, however a warm southerly wind will pull warm and humid air into North Georgia by Christmas Eve.