When is the shortest day of the year? What to know about the start of winter

The start of winter will also mark the shortest day of the year, but it might not look how you’d expect.

The shortest day of the year doesn’t actually mean the earliest sunset of the year.

In fact, the earliest sunset has already happened.

So what does it mean and when will it happen?

Here’s what to know about the 2025 winter solstice:

What is the winter solstice?

The first day of astronomical winter in the Northern Hemisphere is marked by the winter solstice, which takes place every year on Dec. 21 or 22 and marks the shortest day of the year and the longest night.

“The winter solstice is the day with the fewest hours of sunlight throughout the year, making it the “shortest day” of the year,” the Old Farmers Almanac says. “Thankfully, after we reach the winter solstice, the days begin to grow longer and longer again until we reach the summer solstice—the first day of summer and the longest day of the year.”

According to the National Weather Service, the solstice takes place in the Northern Hemisphere “when the sun is directly over the Tropic of Capricorn, which is located at 23.5° south of the equator and runs through Australia, Chile, southern Brazil, and northern South Africa.”

When is the winter solstice?

This year, the winter solstice will officially occur at 9:03 a.m. Central Standard Time on Dec. 21.

While many think of the solstice as being a full day, it’s actually only a moment.

The Old Farmer’s Almanac notes the actual solstice is the moment when the hemisphere is titled as far asway from the sun as possible and “the Sun’s path across the sky is as low in the sky as it can be.”

Can you see the winter solstice?

The answer lies not in what you see at the moment of the solstice, but what happens around it.

By the time the winter solstice arrives, the sun sits at the lowest position in the sky it can.

As a result, the shadow you cast becomes longer and longer as the winter solstice approaches. So if you go outside at noon on the winter solstice, your shadow will be the longest it will be all year.

You can also see days getting longer following the solstice.

“It only gets brighter from here!” the Old Farmer’s Almanac wrote.

When will days start getting longer?

Since the Earth’s orbit around the sun isn’t a perfect oval, the winter solstice does not line up perfectly with the earliest sunset and the latest sunrise of the year, and as a result Chicago will slowly start seeing later sunsets in the lead-up to the solstice, even though days will still technically be getting shorter.

That’s because sunrise will continue to happen later and later in the morning, slowly chipping away at the amount of daylight the Chicago area will see in a given day.

That will continue past the winter solstice on Dec. 21, when the Chicago area will see just under nine hours and 11 minutes of daylight.

From that day forward for the next six months, days will be getting longer, albeit extremely slowly at first. In fact, by the end of December, Chicago will have gained just over three minutes of daylight, with the sun setting at 4:31 p.m. on New Year’s Eve.