Your last chance to see a supermoon in 2025 is this week, with the full moon scheduled to appear on Thursday, Dec. 4. But 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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