AUSTIN (KXAN) — Winter hasn’t even started yet, but we’re already experiencing the earliest sunsets of the year in Central Texas.
5:30 p.m. is the earliest the sun sets each year in Austin. This year, Nov. 25 was the first time the sun set at 5:30 p.m. and it will continue to set at 5:30 p.m. through Dec. 10.
On Dec. 11 the sun sets in Austin at 5:31 p.m. and sunset will continue getting later until late June or early July when we reach the latest sunset of the year at 8:36 p.m.
Unfortunately, while our sunsets will soon start to get later, our sunrises will continue getting later as well. We don’t experience our latest sunrises of standard time until Jan. 4-16 when the sun doesn’t rise until 7:28 a.m.
This, however, is not our latest sunrise of the whole year. Our latest sunrise of the whole year happens the day before we end Daylight Saving Time. On Nov. 4 the sun rose at 7:47 a.m., the latest sunrise of the year.
Why doesn’t the latest sunset occur on the winter solstice?
Several complicated factors mean that the earliest sunset of Standard Time happens before the winter solstice, but the latest sunrise happens after the winter solstice.
Basically, it comes down to errors made by assuming a day is 24 hours long all year round.
A day is really the time it takes to go from one solar noon to the next one. Solar noon is when the sun reaches its highest point in the sky, which rarely happens at exactly noon.
The elliptical orbit around the sun, the tilt of the earth’s axis and the position of the sun within our orbit all help to shift the length of our days away from being an even 24 hours. In reality, sometimes a solar day is longer than 24 hours and sometimes it’s shorter.
All these adjustments and rounding errors, along with the latitude you’re located at, mean that our sunsets stop getting earlier before our sunrises stop getting later, but the shortest day of the year is still on the winter solstice.
On the winter solstice this year, which occurs on Dec. 21, sunrise is at 7:23 a.m. and sunset is at 5:24 p.m. On this day we only get 10 hours, 11 minutes and 38 seconds of daylight in Austin, making for the darkest day of the year.
After that…our days will slowly start getting longer again!