A supermoon is not an official astronomical term, but rather a popular way to describe a full moon that coincides with the Moon’s perigee. As NASA explains, the Moon’s orbit is oval-shaped, so full moons can occur at varying distances. When a full moon happens near perigee, the Moon appears larger and brighter in our skylivescience.com. In fact, NASA notes that the full Moon can look up to ~14% bigger and 30% brighter at perigee than at its farthest pointlivescience.com. Such perigee full moons typically occur only 3–4 times a year, in a rownbcmontana.com. November 2025’s full moon will join October’s Harvest Moon and December’s Cold Moon as a trio of supermoons closing out the yearlivescience.comnbcmontana.com. In short, the Nov. 5 moon is special because its peak fullness almost coincides with its perigee, yielding an extra impressively bright, large Moon in the skylivescience.com.