December's full moon, called the Cold Moon, falls on Dec. 26 for observers in the Western Hemisphere — it happens at 7:33 p.m. Eastern Time (0033 UTC Dec. 27), according to the U.S. Naval Observatory, and as it rises it will be situated amidst the season's brightest constellations.
For New York City observers, the moon will set on Dec. 26 at 7:18 a.m., and rise that evening at about 4:00 p.m Eastern Time. Sunrise is also at 7:18 a.m., and sunset is at 4:34 p.m., so from the East Coast of the U.S. the nearly-full moon and the sun will be in the sky at the same time. Whether one can see the moon reach its exact full phase depends on one's time zone, because the timing of lunar phases depends on the moon's position relative to Earth and the sun. The full moon occurs when the moon is exactly opposite the sun from Earth, (this happens every 29.5 days) so some observers won't see the moon at the moment it becomes full because they will be on the other side of the Earth (by and large in daylight) when it happens.
In some locations the moon becomes full before it rises; the moment of fullness is earlier as one moves westwards and moonrise gets later as one moves south. In Honolulu, for example, the full moon is at 2:33 p.m. Dec. 26, but moonrise isn't until 5:53 p.m. local time. Moving to the east, where the full moon occurs later, one finds that in Tokyo, where the full moon is at 9:33 a.m. local time on Dec. 27, the moon sets by 7:06 a.m.
A consequence of the sun and moon being on opposite sides of the sky is that in the Northern Hemisphere, the moon is visible longer (as the days are shorter), and the situation is reversed in the Southern Hemisphere. The time the full moon is above the horizon in New York City is 16 hours and 13 minutes (moonset is at 8:13 a.m. on Dec. 27). If one is observing from Cape Town, where the full moon is at 2:33 a.m. local time on Dec. 27, the moon rises at 7:57 p.m. on Dec. 26, and sets at 5:29 a.m. on Dec. 27; that means the moon is "up" for 9 hours and 34 minutes.
What this means is that in the Northern Hemisphere winter, the moon tends to rise higher in the sky; for example, from mid-northern latitudes (New York, or Chicago, or Portland, Oregon) the full moon is between 75 and 80 degrees high at about midnight (in New York City, its altitude is 77 degrees when it crosses the meridian the night of Dec. 26-27). In the Southern Hemisphere the moon will be correspondingly lower in the sky; on the night of Dec. 27 - 28 the moon is only about 23 degrees above the northern horizon when it reaches its highest point in the sky.
This is also why moonrise in the Northern Hemisphere gets later as one moves south; the closer one is to the equator the more "even" the length of day — and the time the moon is above the horizon — gets. In the tropics (latitudes between 23 degrees north and 23 degree south) the day length never varies much from 12 hours; in Mexico City (19 degrees north) the longest days are just over 13 hours in the last week of June and the shortest are a bit under 11 hours in December. In Chicago (42 degrees north) the longest day is 15 hours and 13 minutes on the summer solstice (June 21, 2023) and the shortest day is 9 hours and 6 minutes (Dec. 21). In the Southern Hemisphere Hobart, Tasmania, has similar conditions to Chicago; the summer solstice there is on Dec. 21 and the day is 15 hours and 21 minutes long, some 6 hours and 20 minutes longer than the shortest day on June 22.
On the night of the full moon, of the five naked-eye planets, three will be easily spotted. As the sun sets, in the Northern Hemisphere, Saturn will be in the south-southwest, the planet sets at 9:18 p.m. local time in New York City. Fully two thirds of the way up to the zenith from the horizon, at about 58 degrees altitude in the southeast, is Jupiter. Both planets are recognizable by their bright and steady light; often stars will twinkle, but planets will not. Jupiter will be up longer; the planet sets at 2:37 a.m. local time in New York.
Later in the night Venus will rise, at about 4:41 a.m. on Dec. 27 in New York (the rising time will be similar locally in Chicago, Denver, and Salt Lake City). Venus is bright enough that even in the minutes before sunrise (which is at 7:19 a.m.) it is still visible — an interesting exercise is to see how close to sunrise you can still spot the planet against a lightening sky.
The position of the full moon against the background stars changes every hour — it is about one of its diameters every hour. One can even track it with no optical aid; if one stays up all night. When the moon rises in New York it will be in the constellation Gemini, the Twins. As the night progresses the moon will move several degrees closer to Castor, and visibly so.
Mars and Mercury both rise ahead of the sun, but both are lost in the solar glare.
The moon rises in Gemini, one of the bright constellations that marks the Northern Hemisphere winter. Surrounding the full moon one will be able to spot Auriga, Orion, and Taurus — hallmarks of the winter sky. Soon after moonrise — by about 6:30 p.m. in New York — the moon will be to the right of Castor and Pollux. The two stars will appear to be aligned vertically; with Pollux closer to the horizon.
To the right of the moon is Orion, recognizable by the three stars of his belt; early in the evening they too will appear to be vertically arranged, though they assume a more horizontal appearance as the night goes on. The star closest to the horizon is Alnitak, the middle star of the belt is Alnilam, and the westernmost star is Mintaka. To the left of the belt (and above it later on) is Betelgeuse, recognizable by its reddish hue.
Above Betelgeuse is Aldebaran, another orange-red star, it's the brightest star in Taurus, the Bull. Looking to the left of Aldebaran and above the moon is Capella, the alpha star of Auriga, the Charioteer. This group of constellations surrounds the moon, which will be so bright that it will wash out the fainter stars, but the brightest of them should still be visible.
In the Southern Hemisphere, one sees the constellations "upside down" — and it being the austral summer the sun sets much later. In Melbourne, Australia (and similar latitudes), moonrise on Dec. 27 isn't until 9:28 p.m. By 10:00 p.m. the moon is still close to the northeastern horizon, but if one looks directly upwards one will see Betelgeuse, the distinctive reddish star that marks the shoulder of Orion.
From southern latitudes the starts of Orion's Belt appear above Betelgeuse, with Mintaka on the left. Aldebaran will be to the left of Betelgeuse and Procyon, the alpha star of Canis Minor, the Little Dog, on the right. If one continues to look upwards from Orion's Belt one encounters Rigel, a bluish-white star that is Orion's foot, and looking to the right of that one sees the brightest star in the sky, Sirius. Continuing southwards (to the right) and up, one can see Canopus, the brightest star in Carina, the Ship's Keel.
The December moon
The Old Farmer's Almanac calls the December full phase the Cold Moon, and that is certainly true if you live in the Northern Hemisphere's middle latitudes. The Old Farmer's Almanac uses names derived from European settlers and northeastern Native peoples, but there are other ideas as to the significance of a December full moon, even among various indigenous groups. The Lakota, for example, called the December lunation Wanícokan Wi, the moon when the deer sheds their horns, while the Miami people, who originally lived in the area around western Ohio, Indiana and Lake Michigan, called the lunation the "Buck Moon." The Hopi people named the month in which the winter solstice occurs the "Respected Moon."
In China, the December lunation is called Dōngyuè, "Winter Month."
In Jewish calendars the December full moon is in the midst of the month of Tevet; this is the month that Chanukah falls in. In Islamic calendars the December full moon is in the month of Jumada Al Akhira; as the Islamic calendar doesn't adjust to keep it in step with the solar year the same date on the calendar will arrive some 11 days earlier in 2024.
In the Southern Hemisphere many cultures have winter-themed lunar months. The Māori call the December-January lunation Kohi-tātea, or "Fruits are now ripe, and man eats of the new food of the season." The Zulu also had a lunar calendar with the new year beginning in September; the December lunation was called uZibandlela, which refers to the grasses that grow in pathways during the austral summer months, hiding them; the name itself means "ignore the path."
If you're looking to snap a photo of the December full moon, check out our guide on how to photograph the moon. If you don't have everything you need to photograph the night sky, consider our best cameras for astrophotography and best lenses for astrophotography.
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Jesse Emspak is a freelance journalist who has contributed to several publications, including Space.com, Scientific American, New Scientist, Smithsonian.com and Undark. He focuses on physics and cool technologies but has been known to write about the odder stories of human health and science as it relates to culture. Jesse has a Master of Arts from the University of California, Berkeley School of Journalism, and a Bachelor of Arts from the University of Rochester. Jesse spent years covering finance and cut his teeth at local newspapers, working local politics and police beats. Jesse likes to stay active and holds a fourth degree black belt in Karate, which just means he now knows how much he has to learn and the importance of good teaching.