Winter Solstice 2024 brings the shortest day of the year to the Northern Hemisphere today

On December 21, 2024By Littum

The winter solstice is today, bringing the shortest day and longest night of the year to the Northern Hemisphere.

As the official start of the astronomical winter, the sun reaches its southernmost point in the sky as seen from Earth. At noon, it appears directly overhead at the Tropic of Capricorn, located at a latitude of 23.5 degrees south. This position correlates with the shortest day of the year in the northern hemisphere, which is tilted as far away from the sun as possible and in turn experiences the fewest hours of sunlight.

The exact timing of the moment-long winter solstice and official change of seasons took place on Saturday (December 21) at 4:20 AM EST (0920 GMT), according to In the Sky.org.

With winter comes the coldest months of the year. This is because the sun remains much closer to the horizon than in warmer months. The sunlight appears lower in the sky during the day and is less intense and spread over a larger area, giving rise to the cooler temperatures experienced in winter. The good news is that from now on each day will gradually get longer and sunnier as the sun rises earlier and sets later until the summer solstice in June.

Earth experiences seasons because the planet is tilted 23.5 degrees on an axis. This means that each year, as the Earth orbits the Sun, there are periods when the Northern Hemisphere is tilted towards the Sun and receives more sunlight, resulting in summer, and times when the Southern Hemisphere is tilted towards the Sun and receives more sunlight, which marks our winter.

An illustration showing how the Earth's axial tilt determines the seasons.

An illustration showing how the Earth’s tilt affects the seasons as the planet orbits the Sun. (Image credit: Photon Illustration/Stocktrek Images/Getty Images)

Therefore, cooler temperatures experienced in winter are a result of Earth’s tilt rather than the planet’s distance from the Sun. In fact, Earth will reach its closest point to the Sun, also known as perihelion, during the Northern Hemisphere winter on January 4, 2025, according to In the Sky.org.

Perihelion occurs because the Earth’s path around the Sun is not a perfect circle, but rather an ellipse, whereby the distance between the planet and the Sun changes throughout the year. At perihelion, Earth is about 91.4 million miles (147.1 million kilometers) away from the sun, compared to its average distance of about 93 million miles (149.6 million km).

Many festivals and traditions are rooted in the celebration of the winter solstice, which is considered by many cultures to be a time of renewal, hope and the return of light. From tomorrow, daylight will gradually begin to increase. Although this change will be subtle at first, it will become noticeable in about a month as the sun rises earlier and sets later.