Winter Solstice Day

What the winter solstice tool does

The winter solstice is the shortest day of the year and the astronomical start of winter. This tool gives you its date for any year from 1900 to 2050, for either hemisphere. Choose the year and the hemisphere and it returns the day, drawn from accurate astronomical data rather than a rough rule.

How to use it

1. Year. Any year from 1900 to 2050.
2. Hemisphere. Northern or Southern, since winter falls at opposite times in each.

Press Find Solstice and the date appears.

The shortest day, and why

The winter solstice is the mirror of the summer one. It is the moment your hemisphere is tilted as far away from the sun as it gets, given the Earth's 23.5 degree axial tilt. The sun stays low, takes its shortest path across the sky, and is up for less time than on any other day, so you get the fewest hours of daylight and the longest night of the year. At that moment the sun stands directly over the Tropic of Capricorn, 23.5 degrees south of the equator. From the lowest, shortest day, the only way the sun's path can go is back up.

December in the north, June in the south

As with the summer solstice, the hemispheres are opposite, which is why the tool asks which you want. The northern hemisphere has its shortest day in December, while at that same moment the southern hemisphere is having its longest, the height of its summer. Half a year later it reverses. So the winter solstice falls in December for the northern hemisphere and in June for the southern. In the south, the depth of winter and the shortest day is the June date.

Example dates

For the northern hemisphere, the winter solstice falls on 21 December 2025 and 21 December 2026. For the southern hemisphere, winter's solstice lands on 21 June 2025 and 21 June 2026. Like the others, the solstice is one instant worldwide given in universal time, so a date close to midnight can move by a day once you convert it to your own time zone.

The turning point toward longer days

This is why so many cultures have marked the winter solstice for thousands of years. It is the darkest point, but it is also the turn, the day after which the sun begins to climb again and the daylight slowly comes back. That promise of returning light runs through midwinter festivals across the world, Yule among them. One curious detail to match the summer one: the earliest sunset actually falls a couple of weeks before the solstice, around the 8th of December in the north, and the latest sunrise a couple of weeks after, near the 5th of January, even though the solstice itself is the shortest day overall.

Questions people ask

What date is the winter solstice?

In the northern hemisphere it falls around 21 or 22 December, and in the southern hemisphere winter's solstice is around 20 or 21 June. Pick the year and hemisphere for the exact day.

Is the winter solstice the shortest day?

Yes, it has the fewest hours of daylight and the longest night of the year for your hemisphere, because the sun is at its lowest and is up for the least time.

Why is it December in some places and June in others?

Because the hemispheres have opposite seasons. The northern winter solstice is in December, when the south is in midsummer, and the southern winter solstice is in June.

Do the days get longer right after it?

Yes. The solstice is the turning point, after which daylight slowly increases again. Interestingly, the earliest sunset comes a little before the solstice and the latest sunrise a little after.

References

1. U.S. Naval Observatory, Astronomical Applications Department: Earth's Seasons, Equinoxes, Solstices, Perihelion, and Aphelion. https://aa.usno.navy.mil/data/Earth_Seasons