Moon phase calendar

Why some months have no full moon

A lunar cycle is 29.53 days and February is shorter, so roughly once every nineteen years February passes without one — and some other month that year gets two. The second full moon in a calendar month is what people call a blue moon. The names on the cards (Wolf, Snow, Worm and the rest) are the traditional ones American almanacs use; the full moon names page explains where they come from.