The Winter Solstice Is December 21: Why It's the Shortest Day, but Not the Coldest or Darkest Evening

On Monday, December 21, 2026, the Northern Hemisphere reaches its winter solstice: the day with the least daylight of the year. In New York, the Sun will be up for only a little over nine hours. Farther north it is shorter still, and in the far north of Alaska the Sun doesn’t rise at all for weeks around this time.

The solstice is one of the oldest markers on the human calendar, and it comes with a few surprises that most people don’t know about.

Why we have a shortest day

Earth spins on an axis that is tilted by about 23.4 degrees compared with its path around the Sun. That tilt stays pointed in the same direction in space all year. So for half of the year the Northern Hemisphere leans toward the Sun, and for the other half it leans away.

In late December, the north is tilted farthest from the Sun. The Sun takes its lowest path across the sky, rises late, sets early and its light arrives at a shallow angle, spreading the same energy over a larger area. That combination is what makes winter: shorter days and weaker sunlight.

At the solstice, the Sun is directly overhead at noon along the Tropic of Capricorn, in the Southern Hemisphere, where December 21 is the longest day of the year and the start of summer.

It’s not about distance

A common belief is that winter happens because Earth is farther from the Sun. The opposite is true for the Northern Hemisphere. Earth’s orbit is slightly oval, and it makes its closest approach to the Sun in early January, during northern winter. The difference in distance is small, and it is the tilt, not the distance, that drives the seasons.

The earliest sunset isn’t on the shortest day

If you live in the continental United States, your earliest sunset of the year actually comes in early December, about two weeks before the solstice. And the latest sunrise doesn’t arrive until early January.

This happens because the length of a solar day, measured from one noon to the next, is not exactly 24 hours all year. Around the December solstice, solar days run slightly longer than 24 hours, because Earth is moving faster in its orbit near its closest point to the Sun and because of the tilt of its axis. That shifts the whole daylight period a little later on the clock each day. Sunset and sunrise both drift later, so the evenings start getting brighter before the mornings do.

The practical upshot: by the time of the solstice, your evenings are already getting a little lighter.

Why January is colder

The shortest day isn’t the coldest, either. Across most of the United States, average temperatures keep falling into January. That delay is called seasonal lag.

Oceans, lakes and land store heat from the summer and release it slowly. Even as days start lengthening after December 21, the Northern Hemisphere keeps losing more heat at night than it gains during the short days, until the balance tips several weeks later. Coastal areas, near large bodies of water, tend to have a longer lag than inland areas.

How much daylight you get

Daylight on the solstice depends almost entirely on how far north you are:

• Miami: about 10 and a half hours.
• Atlanta and Los Angeles: just under 10 hours.
• New York and Chicago: a little over 9 hours.
• Seattle: about 8 and a half hours.
• Anchorage: under 6 hours.
• Utqiagvik, Alaska’s northernmost town: no sunrise at all, during a period of polar night that lasts about two months.

After the solstice, days lengthen slowly at first and then faster. By late January, many northern cities will have gained close to an hour of daylight.

Celebrations of the light

Many cultures have marked the turning of the year around the solstice, from ancient monuments aligned with the midwinter sunrise or sunset to festivals of light held in the darkest weeks. The idea behind them is the same one astronomy explains: after the solstice, the light starts coming back.

What we think

The solstice is a small, useful lesson in how the planet works. Seasons come from Earth’s tilt, not its distance from the Sun, and the calendar of light doesn’t line up neatly with the calendar of weather.

For anyone who finds the dark evenings hard, there is good news hidden in the details. The earliest sunsets come in early December, so by the time the solstice arrives, the evenings are already getting a little longer.