December 2027 Moon Phases

December 2027 brings the Geminids, generally regarded as one of the year’s strongest and most reliable meteor showers, though a nearly full Moon will get in the way this time, plus the winter solstice and the Full Cold Moon. There’s no eclipse on the calendar this month. Here’s what’s happening and when.

The Geminids peak under a nearly full Moon this year

The Geminids are widely regarded as one of the strongest, most reliable meteor showers of the year, active from early December through around December 17. In 2027 the formal maximum falls around 2:40 PM EST on December 14, in daylight for North America, so the practical viewing nights are the ones surrounding it: December 13–14 and December 14–15. Under ideal dark-sky conditions, the shower’s theoretical rate can reach up to about 150 meteors an hour, though that figure assumes a perfectly dark sky with the radiant directly overhead — real-world counts run lower. Unusually for a major shower, the Geminids are linked to an asteroid rather than a comet: 3200 Phaethon, which shows some comet-like behavior that has led researchers to study whether it’s best described as an active asteroid or a so-called “rock comet.”

This year’s timing is especially unfavorable: the Full Moon falls on December 13, only about a day before the Geminid maximum, so the Moon will still be essentially full and up for nearly the entire night on both of the surrounding observing nights, severely washing out all but the brightest meteors. The Geminids’ radiant, near the star Castor in Gemini, rises in mid-evening and climbs highest around 2 AM local time, so if you want to try, that’s your best window — positioned so a tree, building, or hill blocks the Moon from view. For the timing of other showers throughout the year, see our meteor shower calendar.

The winter solstice arrives December 21

The winter solstice happens when the Sun reaches its southernmost point in the sky, marking the astronomical start of winter in the Northern Hemisphere and the shortest day and longest night of the year. In 2027 that moment falls at 9:43 PM EST on December 21. From here through the June solstice, Northern Hemisphere days keep getting longer and nights shorter — even though the coldest weather is often still weeks away, since the oceans and land take time to catch up with the changing sunlight.

Why it’s called the Cold Moon

December’s Full Moon is widely known as the Cold Moon, a name reflecting the arrival of winter in the Northern Hemisphere. It’s also sometimes called the Long Nights Moon, referring to the long hours of darkness around the winter solstice. These two names come from different traditional naming sources, and their exact cultural origins aren’t always certain — Cold Moon is commonly attributed to Algonquin-speaking peoples in modern full-moon-name references, while Long Nights Moon has been linked to other specific traditions.