Tonight, stargazers are in for a magical show. The first supermoon of 2025 will illuminate the night sky, appearing larger and brighter than any other full moon this year. This phenomenon occurs because the Moon will be at its closest point to Earth in its orbit.

What is a Supermoon?

The Moon’s orbit around Earth is elliptical, meaning its distance from Earth changes throughout the year. When a full moon coincides with the Moon’s closest approach to Earth — called perigee — or comes within 90% of that distance, it is called a supermoon.

The term “supermoon” was coined in 1979 by astrologer Richard Nolle to describe full moons that appear noticeably larger and brighter because they coincide with perigee. Visually, supermoons can appear up to 14% larger and up to 30% brighter than other full moons.

Different astronomers have slightly different definitions. One alternative definition classifies any full moon within 360,000 km of Earth’s center as a supermoon — in which case, the October Harvest Moon might not qualify.

Nevertheless, tonight’s full moon promises a breathtaking sight for anyone looking up at the night sky.