Believe it or not, astronomical winter begins at 4:21 a.m. on December 21st. Astronomically, this is the date and time of the winter solstice in the Northern Hemisphere and the summer solstice in the Southern Hemisphere.

In the Northern Hemisphere, Saturday will be the longest night of the year, and starting Sunday, the sun will rise higher in the sky each day, with daylight lengthening.

Earth’s seasons are determined by its orbit around the Sun and the tilt of the Earth’s axis at 23.5 degrees. This causes the amount of sunlight falling on the Earth’s northern and southern hemispheres to constantly change.

The seasons of the two hemispheres are always opposites – our fall is their spring, while our summer is their winter.

As you travel and enjoy the longest night of the year, the five visible planets will keep you company.

Venus shines above the southwest horizon as darkness falls – you can’t miss it. At 9 p.m. you’ll see yellowish Saturn in the southwestern sky, while bright Jupiter hovers high in the east. Reddish Mars is in the lower left near the horizon. You can see Mercury low in the southeastern sky about an hour before sunrise, and binoculars will help you tremendously in finding the bright, yellowish planet.

The Ursids meteor shower is expected to peak on December 22 and 23, but a bright moon will reduce visibility.

On December 30th, you’ll find out what my “Top Space Story of 2024” is, and on January 1st, WTOP’s monthly edition, “What’s Up In DMV Skies,” will premiere. We’ll keep you up to date on what’s happening in the sky and space-related events on the ground every month.

I wish everyone a happy holiday and a happy new year.

Follow Greg Redfern on Facebook, Bluesky and his daily blog to stay up to date with the latest news in astronomy and space exploration.

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