Winter Solstice 2024: marks shortest day of the year

December 21 marks Winter Solstice, the shortest day of 2024 as well as the longest night of the year.

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The winter solstice, which is the shortest day and longest night of the year, will occur on Saturday, December 21, 2024, at 4:20 am ET marking the arrival of Winter in the Northern Hemisphere.

This celestial event represents a key moment in Earth’s annual orbit, as daylight hours reach their minimum while the night stretches to its longest duration.

Why Is the Winter Solstice the Shortest Day of the Year?

The Earth's 23.4-degree axial tilt is the primary reason behind the varying lengths of daylight throughout the year.

During the Northern Hemisphere’s summer, the North Pole tilts towards the Sun, granting longer days. In contrast, during the winter, the North Pole tilts away from the Sun, resulting in shorter days and longer nights.

On the solstice, the Sun appears at its lowest point in the sky, making it the day with the least amount of sunlight.

For instance, New York will experience just 9 hours and 15 seconds of daylight, while Los Angeles will see slightly more at 9 hours and 53 minutes.

Interestingly, while the solstice represents the shortest day, the earliest sunset doesn't always occur on the same day.

For example, in New York, sunset on December 8 was at 4:28 p.m. ET, while on the solstice, it will be four minutes later at 4:32 p.m. ET.

Does the Winter Solstice Always Fall on December 21?

Not exactly. While the solstice typically occurs on December 21 or 22, it can occasionally fall on December 20 or 23, due to the Earth's elliptical orbit and how time is measured by the Gregorian calendar.

The rarest solstice dates are December 20 and 23. For example, the last December 23 solstice took place in 1903, and the next one won’t occur until 2303. The next December 20 solstice will be in 2080.

The Winter Solstice: A Moment for Stargazing

The long night provides an excellent opportunity for skywatchers. The winter months offer a fantastic view of the Orion constellation and the star-forming gas clouds surrounding it.

As Earth orbits the Sun, different parts of the night sky become visible, and the winter solstice offers a particularly clear view of the galaxy's other half, according to Darren Baskill, a physics and astronomy lecturer at the University of Sussex.

The solstice also marks the beginning of astronomical winter in the Northern Hemisphere, while in the Southern Hemisphere, it signals the summer solstice, the longest day of the year.