Winter is almost here, along with your last chance to see a supermoon in 2025. The full moon is scheduled to appear tonight, on Thursday, Dec. 4, and even if you don't make plans to go out and see it, you'll probably spot it anyway since it'll be the brightest thing in the dark night sky.
The December Cold Moon is the third of four consecutive supermoons and the last one of 2025. Supermoons tend to come in packs of four thanks to how the moon orbits the Earth. The orbit is elliptical, meaning the moon is closer during some months and farther away in others. When it is close to Earth, it is referred to as perigee, and full moons during perigee are considered supermoons.
The size difference between an average full moon and a supermoon can be subtle. NASA
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Since it is closer, the moon will be slightly bigger 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 farthest point from Earth, a phenomenon known as apogee. Thus, it is the best time to view a full moon outside of special events like blood moons or lunar eclipses.
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When is the full moon in December?
The Farmers' Almanac reports that the full moon will reach peak illumination at 6:14 p.m. ET on Thursday, Dec. 4. It should be dark enough to see for most of the US, but if not, it will remain full all night. Those who are not able to see it due to the weather can see a moon that is more than 90% full from Dec. 2 to Dec. 6.
You do not need any special equipment to see the moon, as it will be the brightest thing in the night sky by a wide margin. People who want to see more detail can certainly use a telescope or binoculars if they choose, which will make the various craters and textures of the moon easier to see.
The December full moon is often referred to as the Cold Moon, as it typically occurs when the weather starts to become quite chilly. The moon is earning its name this time around, as the Thanksgiving polar vortex is scheduled to stick around for a while. The polar vortex will drive down temperatures this week, so if you do go outside, make sure to bundle up.