Even though snow and cold have already arrived in some parts of the U.S., the astronomical start to winter begins on Thursday.
The first day of winter coincides with the winter solstice, which is also the shortest day of the year in terms of hours of sunlight.
Despite starting near the end of the months they begin in, astronomical seasons and meteorological seasons both last for approximately three months.
Here's what to know about the winter solstice and the first day of winter:
Get top local stories in Philly delivered to you every morning. >Sign up for NBC Philadelphia's News Headlines newsletter.
What is the winter solstice?
The winter solstice marks the point when the North Pole is at its furthest location away from the sun, creating the atmosphere for shorter hours of sunlight.
Though the day of the solstice is always marked, the solstice itself is only the moment that the Northern Hemisphere is tilted at its furthest point away from the sun, according to the Farmer's Almanac.
U.S. & World
Stories that affect your life across the U.S. and around the world.
As the solstice marks the changing of seasons, the event also holds significance to many cultures. Several ancient structures were built as ways to track the seasons, including Stonehenge in England and Newgrange in Ireland.
Additionally, the solstice can also be seen as the time in which the sun's path reaches its most southerly point of the sky, with the opposite effect being witnessed in the Southern Hemisphere.
According to the Farmer's Almanac, the word solstice originates from the Latin words sol and sistere, translating to "sun" and "to stand still" respectively, loosely translating to "sun stands still."
When is the 2023 winter solstice?
Though the day of the solstice is always marked, the solstice itself is only the moment that the Northern Hemisphere is tilted at its furthest point away from the sun, according to the Farmer's Almanac.
According to the National Weather Service, this year's winter solstice will occur at 10:27 p.m. ET/7:27 p.m. PT on Thursday, Dec. 21, marking the official start of winter.
When is the first day of winter?
After the winter solstice concludes, the sun begins to advance northward all the way up until the summer solstice occurs in the Northern Hemisphere, marking when the sun is most closely tilted to the hemisphere.
While the solstice and shortest day of the year will both occur on Dec. 21, the following day is recognized as the first full day of winter.
When are the next astronomical season changes?
Below is a list of the astronomical season changes we can expect to see following the upcoming winter solstice next month:
- Vernal Equinox (Spring): March 20, 2024, 11:06 p.m. ET/8:06 p.m. PT.
- Summer Solstice (Summer): June 20, 2024, 4:51 p.m. ET/1:51 p.m. PT.
- Autumnal Equinox (Fall): Sep. 22, 2024, 8:44 a.m. ET/5:44 a.m. PT.
