Your last chance to see a supermoon in 2025 is fast approaching. The full moon is expected to appear this week, on Thursday, December 4. And even if you don’t plan to go out and see it, you’ll probably notice it anyway – it’ll be the brightest thing in the night sky.
December’s Cold Moon is the third of four consecutive supermoons and the last of 2025. Supermoons tend to come in groups of four thanks to the way the Moon orbits Earth. The orbit is elliptical, meaning the moon is closer in some months and further away in others. When it is close to Earth, it is called perigee, and full moons during perigee are considered supermoons.
The apparent difference in size between an average full moon and a supermoon may be subtle, but it is there.
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As it is closer, the moon will be slightly larger and brighter in the night sky. According to NASA, a supermoon is 14% larger and 33% brighter than a micromoon, which occurs during full moons, when the moon is at its furthest point from Earth, a phenomenon known as apogee. So this is the best time to observe the full moon outside of special events. like blood moons or lunar eclipses.
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When is the December full moon?
The Farmer’s Almanac reports that the December full moon will occur on the evening of December 4. It will reach peak illumination at 6:14 p.m. ET. Thanks to the recent daylight saving time change, it should be dark enough to see most of the United States, but if not, it will stay full all night. Those who can’t see it due to weather can see a moon more than 90% full from December 2 to 6.
You won’t need any special equipment to see the moon, as it will be by far the brightest object in the night sky. Those who want to see more detail can certainly use a telescope or binoculars if they wish, which will allow a better view of the moon’s different craters and textures.
The December full moon is often called the Cold Moon because it usually occurs when the weather starts to get quite cold. The Moon deserves its name this time around, as a polar vortex is expected to hit the United States during Thanksgiving and persist for some time afterward. The polar vortex will cause temperatures to drop across much of the United States this week, so if you go out, be sure to bundle up.
