It has been cold far north of the equator for many weeks, but astronomically speaking, the winter season does not begin until the solstice. That happens this Saturday, when the Northern Hemisphere has the shortest day and longest night of the year and the Southern Hemisphere has the longest day and shortest night of the year.

Here’s everything you need to know about this week’s solstice – and why it’s important.

Winter solstice 2024: time and date

The winter solstice in the Northern Hemisphere (and the summer solstice in the Southern Hemisphere) occurs on Saturday, December 21st at 4:19 a.m. EST. At this exact time the sun shines over the Tropic of Capricorn. When viewed from the Northern Hemisphere, it appears to be the southernmost point.

“The word Solstice comes from the Latin words Sol sun and Sister (stand still),” Shyam Balaji, a researcher in astroparticle physics and cosmology at King’s College London, said in an email. “It refers to the point at which the sun’s apparent movement north or south pauses before reversing direction.”

Winter Solstice 2024: Why It’s Happening

“The December solstice occurs because the Earth is tilted about 23.5 degrees on its axis relative to its orbit around the sun,” Balaji said. “This bias means that different parts of the Earth receive different amounts of sunlight throughout the year. During the December solstice, the Northern Hemisphere is tilted furthest away from the Sun, resulting in the shortest day and longest night of the year for that hemisphere.”

Additionally, the sun is lower in the sky and takes a shorter path through the sky. Indication of cold temperatures in the northern hemisphere.

Winter solstice 2024: Earth in “perihelion”

The seasons are related to the name of the Earth and have nothing to do with how close the Earth is to the Sun. Earth will reach perihelion – the closest approach to the sun in its slightly elliptical orbit – on January 3, 2025, just two weeks after the solstice.

Instead, the winter solstice marks the moment when the sun passes over the Tropic of Capricorn and the days afterward begin to grow longer. Therefore, the winter solstice is generally celebrated as the rebirth of the sun and the beginning of the solar year.

Winter solstice 2024: How long is the shortest day of the year?

The length of the shortest day varies depending on your location on the planet. Here are some examples from the Northern Hemisphere:

• New York: 9 hours and 15 minutes.
• Los Angeles: 9 hours and 53 minutes.
• London: 7 hours and 49 minutes.

“The exact duration depends on how far north or south you are from the equator,” Balaji said. “After the December solstice, days begin to get longer in the Northern Hemisphere.”

I wish you clear skies and big eyes.