What To Know About This Weekend's Cold Moon—The Last Full ...

12 hours ago

Forbes

Topline

December's Cold Moon—the last full moon of the year—will appear in the sky overnight this weekend and coincide with a rare lunar event in which observers can see it rise and set at its most extreme points on the horizon.

The last full moon of 2023, the cold moon, on Dec. 26, 2023.

Getty Images Key Facts

The moon will reach peak illumination at around 4 a.m. EST on Sunday, and will rise and set at its northernmost points on the horizon of any moon in decades.

The moon will rise and set at the extreme points due to two phenomena coinciding at the same time: "lunar precession," which describes an 18.6-year cycle in which the moon wobbles on its axis, and “major lunar standstill,” when the moonrise and moonset positions are made even more extreme.

The moonrise and moonset won’t occur this far north on the horizon again until 2043.

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Tangent

The weekend will bring the Geminid meteor shower, expected to light up the sky with dozens of shooting stars—some shining green and purple—every hour.The meteor shower is expected to be visable Friday night but could be washed out by the nearly full moon.

What To Watch For

The Griffith Observatory will host a live broadcast of the full moon rising Sunday.

Key Background

The full moon in December was originally called a cold moon by Native Americans because it coincides with the long, cold nights of winter, according to the Maine Farmers' Almanac. It has also been called the Moon before Yule and the Oak Moon by Europeans, because it is the full moon before the winter solstice, and the Long Night Moon because the path of the sun makes it visible for longer than other moons. Other cultures have called it the Chang'e moon, frost moon and winter moon, among other names.

Big Number

16 hours 3 minutes. That's how long the moon will be in the sky from Sunday into Monday. Click here to see specific moonrise times for different areas of the U.S.