SEATTLE — It's official – pre-7 p.m. sunsets have arrived in Seattle.
The sun set before 7 p.m. for the first time this season on Tuesday, officially going down at 6:59 p.m., according to the National Weather Service.
Not only was it the first sunset before 7 p.m., but there are now more nighttime than daytime hours. The sun rose at 7:01 a.m. on Tuesday, meaning there were 11 hours and 58 minutes of daylight.
The number of daylight hours will only decrease until the winter solstice on Dec. 21, when Seattle will see its shortest day of the year. The sun will rise at 7:54 a.m. and set at 4:20 p.m. for a measly eight hours and 26 minutes of daylight.
The first pre-6 p.m. sunset will occur on Oct. 27, when the sun will set at 5:59 p.m. The sun will start to set in the 4 p.m. hour just a short time later when clocks roll backward on Nov. 5.
Why does the sun set earlier in the fall and winter?
The length of time between sunrise and sunset in the northern and southern hemispheres has to do with how the earth is tilted on its axis.
During the northern hemisphere's spring and summer, the north pole is tilted toward the sun, and during the fall and winter, the north pole is tilted away from the sun.
This means that physically, the sun's arc across the sky is longer in the spring and summer, when the north pole is closer to the sun and shorter in the fall and winter, when the north pole is tilted away from the sun, according to the U.S. Navy's Astronomical Applications Department.
