Supermoon to peak soon in California sky. What to know about December’s full moon
A massive moon will soon rise in the night sky above California night.
The last full moon of 2025 will also be a supermoon, appearing bigger and brighter than usual to local stargazers.
It’s the third larger-than-usual moon in a row to appear above the Golden State, following the Oct. 6 harvest moon and the Nov. 5 beaver moon.
This “rare streak” presents an uncommon opportunity for skywatchers to see another luminous moon, according to National Geographic.
Here’s how to observe the final supermoon of the year.
When to watch December supermoon in California
The 12th full moon of 2025 will reach peak illumination at 3:14 p.m. on Thursday, Dec. 4, according to online calendar Time and Date.
What is a supermoon?
“A ‘supermoon’ occurs when a full moon coincides with the moon’s closest approach to Earth in its elliptical orbit, a point known as perigee,” NASA said.
The full moon looks larger than normal because it’s at its closest to Earth, National Geographic said.
“At this time, the moon can appear up to 14% larger and 30% more luminous than when it’s at its farthest point from our planet, known as its apogee,” the publication said.
During perigee, the moon is about 356,000 kilometers away from Earth, compared to a distance of about 406,000 kilometers at apogee, according to National Geographic.
How did cold moon get its name?
The December full moon is called the cold moon, according to the Old Farmer’s Almanac.
Originating from the Mohawk peoples, the name refers to the seasonal drop in temperatures that occur throughout the last month of the year.
In the United States, the December full moon has also been called the long night moon, since it rises amid some of the longest winter nights, as well as the drift clearing moon, the snow moon, the frost exploding trees moon and the hoar frost moon, the almanac said.
According to the Almanac, ancient pagans in Europe named it the “moon before yule,” referencing the winter solstice Yuletide festival celebrating the return of sunshine and longer days.
How many supermoons will we see in 2025?
December’s cold supermoon is the third of three supermoons scheduled to take place in 2025, according to the Old Farmer’s Almanac.
California is one of the top 10 states in the nation to view the cold supermoon, according to the Supermoon Visibility Index from Action Network.
California ranked No. 6 on the list, with New Mexico landing the top spot. The index based its rankings on “sky clarity, humidity, elevation, and darkness,” the Action Network said.
Can full moon affect the weather?
The extra-large winter moon can result in slightly higher tides, called king tides, along California’s coastlines, “though the effect is modest,” the Old Farmer’s Almanac said.
Best ways to see December supermoon? Take photos?
According to National Geographic, the supermoon can best be spotted in the eastern horizon right after sunset, around 4:45 p.m.
“It can appear enormous, not only because it is at perigee, but also thanks to the moon illusion, a quirk of human perception that makes objects near the horizon seem larger than when high overhead,” National Geographic said.
To capture the most dramatic views of the cold moon, you can frame the big, luminous orb against hills, trees and buildings, the publication said.
NASA advised amateur astronomers to take photos of the supermoon with their phone flash off.
Cameras should be focused on the moon, not the sky, and tripods can help stabilize the image, the space agency said.
When is the next supermoon in California?
Californians won’t have to wait long to see the next supermoon. It will rise in early January.
According to the Old Farmer’s Almanac, the wolf full moon on Saturday, Jan. 3, will also be a supermoon.
National Geographic called the event a “cosmic party” since it will be the fourth consecutive supermoon to rise above the United States.
This story was originally published December 4, 2025 at 9:50 AM.
