Winter Solstice: Why the Noon Sun Sits Lowest and the Day Is Shortest in December

The December solstice is the turning point of the northern year. It brings the shortest day and the longest night, and after it the days begin to grow longer again. It opens astronomical winter in the Northern Hemisphere. In the Southern Hemisphere it brings the opposite, the longest day.

This guide explains what makes that date special. It gives the 2026 time from the U.S. Naval Observatory and works through a noon-height rule you can test in the Orbit Dial. It also clears up a common surprise: Earth is closest to the Sun only about two weeks after this solstice.

What happens at the December solstice

The Naval Observatory says the solstices are the two dates in the year when Earth's axis is most tilted toward or away from the Sun. In December the Northern Hemisphere is tipped away. NASA's Earth Facts page gives the tilt as 23.4 degrees. It says that when the north leans toward the Sun it has summer and the south has winter, and that six months later the situation flips. So in December the south gets the more direct sunlight.

NASA's Earth Observatory describes where the Sun stands. At the December solstice, the Sun is directly over the Tropic of Capricorn. NASA's Night Sky Network places that line 23.5 degrees south of the equator.

NASA's Watch the Skies blog spells out what this means for daylight. The December solstice brings the shortest day and longest night of the year to northern places such as the United States. All locations north of the equator see daylight shorter than 12 hours, and locations south of it see more. In the south, the same blog says, it is the longest day and shortest night. After the solstice, northern days get longer.

The drawing above shows the December solstice for a place at 40 degrees north latitude.

The 2026 date and time

The Naval Observatory's table for 2026 lists the December solstice on December 21 at 20:50 Universal Time (UT). Set to Eastern Time, the same table gives 15:50 ST, which is 3:50 p.m. Eastern Standard Time. Of the four solstices and equinoxes on that table, this is the only one still ahead when this guide was published on November 10, 2026. It is about six weeks away.

Sources do not all agree on the clock time. One NASA skywatching page lists the December 2026 solstice as December 21 at 15:03 UTC. The Naval Observatory table says 20:50 UT. Both name December 21, and this guide follows the Naval Observatory table. For the exact moment, check the official table.

The date can also look different in other sources. The National Centers for Environmental Information (NCEI, part of NOAA) gives December 22 as the approximate date, and says the exact dates of the solstices and equinoxes vary because an extra day is needed every fourth year. The Naval Observatory says the winter solstice falls on or about December 21.

How low the noon Sun sits

A rule from NASA's Radio JOVE training module turns the tilt into a number. On an equinox, the noon Sun's altitude, its angle above the horizon, equals 90 degrees minus your latitude. The module's example is a person at 40 degrees north, where the noon Sun stands 50 degrees high. For the solstices, the module says to add or subtract 23.5 degrees.

In December you subtract. At 40 degrees north the noon Sun stands a little over 26 degrees high, which is 23.5 degrees lower than at an equinox. In June the same place gets a little over 73 degrees. Our summer solstice guide shows that side of the year.

The Naval Observatory gives the reason. The Sun's declination, its angle north or south of Earth's equator, goes from +23.4 degrees at the summer solstice to -23.4 degrees at the winter solstice. NASA's Night Sky Network adds that during the winter solstice the Sun is at its lowest point at solar noon for the year.

Why the shortest day is not the earliest sunset

The Naval Observatory says the day with the least daylight is the winter solstice, on or about December 21. Sunset and sunrise follow a slightly different calendar. At 40 degrees north, the earliest sunset comes around December 8, and the latest sunrise comes around January 5.

Those dates sit about two weeks on either side of the solstice. So evenings stop getting earlier a couple of weeks before the shortest day, and mornings keep getting later for a couple of weeks after it. For exact sunrise and sunset times, use a table made for your city.

Common mistakes

• Thinking winter comes because Earth is far from the Sun. Perihelion, Earth's closest point, falls in early January, about two weeks after the December solstice, according to the Naval Observatory. Its 2026 table lists January 3 at 17:15 UT. NASA's Space Place says Earth's distance from the Sun is not the cause of the seasons. Our guide to perihelion and aphelion goes deeper.
• Calling it the first day of winter everywhere. In the Southern Hemisphere the same moment brings the longest day.
• Mixing astronomical and meteorological winter. NCEI says Northern Hemisphere meteorological winter is December, January and February and follows the temperature cycle. Astronomical winter begins at the solstice.
• Expecting the earliest sunset on the solstice. At 40 degrees north it comes around December 8, about two weeks earlier.
• Trusting every clock time you find. One NASA page and the Naval Observatory table differ on the 2026 hour. Check the table before you plan around a minute.

Try it in the instrument

Open the Orbit Dial and set the sky to the December solstice. The dial takes a date in 2026 and a latitude, and it shows the height of the noon Sun and the length of the day. The target date is December 21, the date in the Naval Observatory's table. That date was still ahead when this guide was published, but the dial lets you set any date in 2026. The game accepts a window of dates, not one exact minute, and the window gets narrower from Bronze to Gold.

Use the rule from this guide to check yourself. Pick 40 degrees north. At an equinox, NASA's example puts the noon Sun at 50 degrees. As you move the date toward December 21, the noon height should fall by about 23.5 degrees and then stop dropping. That stopping point is the solstice, and the day should be at its shortest of the year there.

Then try 23.5 degrees south, the latitude of the Tropic of Capricorn. NASA says people there get their zero-shadow day on the December solstice, so the noon Sun should reach 90 degrees. The tilt behind these numbers is 23.4 degrees in NASA's Earth Facts, and NASA's rule rounds it to 23.5.

Questions people ask

Is it summer in the Southern Hemisphere at the December solstice?

Yes. NASA's Watch the Skies blog says the southern half of the globe has its longest day and shortest night then. NASA's Earth Facts page explains the pattern: when one hemisphere leans toward the Sun it has summer, the other has winter, and six months later the roles swap.

Where is the Sun directly overhead on the December solstice?

Over the Tropic of Capricorn, 23.5 degrees south of the equator, according to NASA's Earth Observatory and Night Sky Network. People on that line see a zero-shadow day, when objects cast a minimal shadow at noon.

Why do some sources say December 22?

Sources give approximate dates. NCEI lists December 22 for the winter solstice. The Naval Observatory says on or about December 21, and its 2026 table gives December 21. The exact day shifts from year to year, so use the table for the year you care about.

Sources

• Earth's Seasons - Equinoxes, Solstices, Perihelion, and Aphelion, U.S. Naval Observatory, Astronomical Applications Department. https://aa.usno.navy.mil/calculated/seasons?year=2026&tz=0&tz_sign=1&tz_label=true&dst=false&submit=Get+Data. Opened November 10, 2026.
• The Seasons and the Earth's Orbit, U.S. Naval Observatory, Astronomical Applications Department. https://aa.usno.navy.mil/faq/seasons_orbit. Opened November 10, 2026.
• Sunrise and Sunset Times Near the Solstices, U.S. Naval Observatory, Astronomical Applications Department. https://aa.usno.navy.mil/faq/rs_solstices. Opened November 10, 2026.
• Facts About Earth, NASA Science. https://science.nasa.gov/earth/facts/. Opened November 10, 2026.
• Seeing Equinoxes and Solstices from Space, NASA Science, Earth Observatory. https://science.nasa.gov/earth/earth-observatory/seeing-equinoxes-and-solstices-from-space-52248/. Opened November 10, 2026.
• Tropical Solstice Shadows, NASA Science, Night Sky Network. https://science.nasa.gov/solar-system/skywatching/night-sky-network/tropical-solstice-shadows/. Opened November 10, 2026.
• December Solstice Brings Winter, Summer Seasons, NASA, Watch the Skies blog. https://www.nasa.gov/blogs/watch-the-skies/2021/12/20/december-solstice-brings-winter-summer-seasons/. Opened November 10, 2026.
• Citizen Science Training Modules, Training Module 0.0: Introduction to the Sun, NASA Radio JOVE Project (radiojove.gsfc.nasa.gov). https://radiojove.gsfc.nasa.gov/citizen_science/training/TM0.0_The_Sun_Introduction.pdf. Opened November 9, 2026.
• Meteorological Versus Astronomical Seasons, NOAA National Centers for Environmental Information. https://www.ncei.noaa.gov/news/meteorological-versus-astronomical-seasons. Opened November 10, 2026.
• What Causes the Seasons?, NASA Space Place. https://spaceplace.nasa.gov/seasons/en/. Opened November 10, 2026.

We opened each source ourselves on the date shown. The drawings are our own and were checked against the numbers in these sources.

Read next

• Summer SolsticeAt the June solstice, Earth's axis leans the Northern Hemisphere as far toward the Sun as it ever goes, so the noon Sun stands highest there.
• Perihelion and AphelionEarth is closest to the Sun around January 3, in the middle of northern winter.