Per
Space.com:
The December full moon is sometimes known as the "Cold Moon" in reference to the plummeting temperatures that are common this time of year and also as the "Long Night Moon," to reflect the lengthening nights and shorter days as the northern hemisphere sinks deeper into the winter months.
This month's full moon will occur as Earth's natural satellite passes within 90% of perigee, the closest point to our planet in its 27-day elliptical orbit, giving rise to a majestic "supermoon." Its close proximity to Earth can make a supermoon appear up to 14% larger and 30% brighter than the smallest full moon of the year — sometimes referred to as a micromoon — when viewed with the naked eye.
