A cold supermoon is on its way. On December 4, Earth’s satellite will delight us with one of the last astronomical spectacles of 2025. Not only will it be the last full moon of the year, but it’s also a cold moon—which refers to the frigid temperatures typical of this time of year—and, finally, a supermoon. Here’s how and when best to enjoy this spectacle of the year-end sky.
What Is a Supermoon?
The term supermoon refers to a full moon that occurs when our satellite is at perigee, the point at which its orbit brings it closest to our planet. (The moon’s orbit is elliptical, and its distance from Earth varies between about 407,000 km at apogee, the point of maximum distance, and about 380,000 at perigee.)
In addition to being the third consecutive supermoon of the year, as reported by EarthSky, it will be about 357,000 km away from us, making it the second-closest full Moon of the year. Consequently it will also be the second-largest and brightest.
Although most of us won’t notice any difference in size compared to a normal full moon (it appears up to 8 percent larger to us), its brightness could exceed that of an ordinary full Moon by 16 percent. This time, moreover, it will be 100 percent illuminated just 12 hours after its perigee.
The Cold Supermoon
In addition to its name, which refers to the cold temperatures of this period, December’s full moon will be the last of 12 full moons in 2025 and the highest of the year. With the winter solstice approaching on December 21, the sun is at its lowest point in the sky, so the full moon is at its highest point. In other words, this means that the super cold moon will be particularly high in the sky. As EarthSky points out, however, it is not the closest full Moon to the December 21 solstice. While it occurs 17 days before, the first full moon of 2026 will occer on January 3—just 12 days ater teh solstice. That will be the fourth and last consecutive supermoon.
How to Enjoy the Show
Although the moon may appear full both the night before and the night after, the exact time of the full moon is scheduled for 6:14 pm ET on Thursday, December 4. In general, moonrise is the best time to be subject to the so-called lunar illusion, during which the moon appears larger than usual to us. NASA still doesn’t have a scientific explanation for why this happens, but as you might expect, the effect is greatest during a supermoon. Weather permitting, therefore, find an elevated place or meadow with an unobstructed view of the eastern horizon and enjoy the last moon show of the year.
This story originally appeared on WIRED Italia and has been translated from Italian.
