How Many Days in December?

From decem, “ten”: the tenth month of the old Roman calendar. The winter solstice, the shortest day in the Northern Hemisphere, is around December 21.

A quick way to remember month lengths is the knuckle rule: make two fists and count across your knuckles and the gaps between them. Every month that lands on a knuckle has 31 days; every month in a gap has 30, except February. Or use the rhyme: “Thirty days hath September, April, June and November…”