CNN News:2020年有13个满月 赏月奇怪接踵而至

On average, how many full moons are there in a year? 11, 12, 10 or 14. In most years there are 12 full moons one occurring per month.
But this year there will be 13 with two full moons in October and when you have two full moons in one month, you have what's said to be a "blue moon".

But blue is just one of the 13 named moons we'll have this year, the others include the "worm moon", "buck moon", "sturgeon moon". According to the Farmer's Almanac, Native Americans gave them these names to keep track of the seasons. January's "wolf moon" is likely because wolf packs were heard howling in January. March's "worm moon" is named for signs of earthworms appearing in the warmer ground. To add to this "moon gazing", there's a pair of penumbral lunar eclipses coming this summer.