Your last chance to see a supermoon in 2025 is quickly approaching. The full moon is due to appear this week on Thursday, December 4th. And even if you don't plan to go out and see it, you'll probably still notice it – it will be the brightest thing in the night sky.
December's Cold Moon is the third of four consecutive supermoons and the last one of 2025. Supermoons tend to occur in groups of four due to the way the Moon orbits the Earth. The orbit is elliptical, meaning that the Moon is closer in some months and further away in others. When it is close to Earth, it is called perigee, and a full moon during perigee is considered a supermoon.
The apparent difference in size between an average full moon and a supermoon may be slight, but it is there.
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Because 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 a full moon when the Moon is at its farthest point from Earth—a phenomenon known as apogee. Thus, this is the best time to view the full moon outside of special events. like blood moons or lunar eclipses.
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When is the full moon in December?
Farmer's Almanac reports that the December full moon will occur on the evening of December 4th. It will reach maximum illumination at 6:14 pm ET. Thanks to the recent change to Daylight Saving Time, most of the US should be dark enough to see, but if it isn't, it will be full all night. Those unable to see it due to weather will be able to see the 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 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 do various craters of the Moon and textures are easier to see.
The full moon in December is often called the Cold Moon because it usually occurs when the weather starts to get quite chilly. This time, the Moon has earned its name as a polar vortex is set to hit the US around Thanksgiving and will remain there for some time after that. polar vortex will lower the temperature across much of the US this week, so if you do go out, be sure to brace yourself.
