Credits: Pixabay/AlainAudet
Winter doesn’t officially arrive until the solstice. According to the U.S. Naval Observatory, the 2024 winter solstice — the precise moment when the Sun appears furthest south in the sky — falls at 4:21 a.m. Eastern Time (EST) on Saturday, Dec. 21, in northern hemisphere.
Throughout the Northern Hemisphere, the solstice day has the fewest hours of sunlight and the night has the most hours of darkness. (In the Southern Hemisphere, where this solstice marks the start of summer, days are now longer and nights shorter.) However, the first sunset and last sunrise of the year do not coincide with the shortest day. This happens because the Earth’s orbit around the Sun is not a perfect circle and the tilt of our planet’s axis is not aligned with the solstice.
The Naval Observatory website has this great tool that will show you Earth’s seasons from 1700 to 2100.
The exact dates of first sunset and last sunrise depend on latitude, but the sequence always remains the same: first sunset, shortest day, and last sunrise. At 40° north latitude, the earliest sunset comes around December 7th and the latest sunrise around January 4th. The dates are closer together at higher latitudes and further apart at lower latitudes.
The southern position of the Sun causes two other notable effects. First, midday shadows appear longer on the solstice than at any other time of the year. You can demonstrate this yourself by using a building or other stable structure (even a stick firmly anchored to the ground will work) and marking the length of its shadow on the ground at local noon (when the Sun is in the south). The shadow will be longest on the day of the solstice.
Related: The National Weather Service on the seasons and the winter solstice
Second, the Sun rises and sets further south on the solstice. Simply find a spot with a clear view of the horizon to the southeast or southwest. It then fixes the position of the Sun relative to a convenient reference point as it rises or sets for a few weeks around the solstice. You will find that the Sun appears further south during the solstice.
It may come as a surprise that in many cultures this dark and dreary time of year marked an occasion to celebrate the Sun. The peoples of Mesopotamia, Persia, Babylon, and even ancient Greece and Rome all celebrated festivities between the end of December and the beginning of January, rejoicing in the imminent triumph of the Sun over darkness. The life-giving Sun had “bottomed out” and was beginning its long march northward, foreshadowing a warmer climate in the future.
This story was originally published on December 22, 2023.
