In addition to adorable socially-distanced trick-or-treaters, we’ll be treated to another phenomenon this Halloween – a rare Halloween Blue Moon! These days, a blue moon refers to the second blue moon in a month. When it falls on Halloween that’s a Halloween Blue Moon! In the past, a blue moon meant the third full moon in a season with four full moons instead of three. Fun fact: all Halloween full moons are blue moons because they’re all the second ones in the month as full moons occur every 29.5 days.
The blue moon won’t actually look blue, but it will certainly add to the ominous atmosphere if you’re walking around after dark on the 31st!
According to Space.com, “We can also call this Halloween full moon the Hunter’s Moon, the traditional name for the first full moon after the Harvest Moon.” The Harvest Moon, which occurred on October 1, is the one that falls closest to the autumnal equinox.
If you want to see the blue moon it will be visible from sunset on October 31 to sunrise the next day, with the best visibility late at night and into the early morning when the moon is highest in the sky.
While there was a Halloween Blue Moon back in 2001, it was only visible from the Central and Pacific time zones. This is the first time since 1944 that a Halloween Blue Moon will be visible from everywhere on Earth so be sure not to miss out! If you do, the next one should be in about 19 years, which is how often a Halloween Blue Moon occurs.