Nothing says “spooky Halloween” quite like a full moon, and the full moon on October 31 this year is extra special.
That’s because the full moon on Halloween is a blue moon.
Despite its name, a blue moon is not blue in color. Instead, it’s the rare occurrence of a second full moon in a single month.
October’s first full moon, the harvest moon, will occur on October 1 at 5:05 p.m. EDT, and the second full moon will occur on October 31 at 10:49 a.m. EDT.
The harvest moon is called that because it falls closest to the autumnal equinox on September 22.
October’s second full moon can be considered the hunter’s moon. According to early American folklore, this moon signals that it is time to start hunting for the winter. With the crops harvested and the moon high, it would be easier to see wild animals.
Even though the full moon will officially happen in the morning on Halloween, it will still appear full that night.
Here’s a video that explains the phenomenon and the history of the term “blue moon”:
A typical year sees one full moon every month for a total of 12 full moons in a year.
This year is special, however, because we’re getting 13 full moons, something that only happens about every two and a half years. The last time we saw a blue moon was March 31, 2018, and the next blue moon after this year won’t happen again until Aug. 31, 2023.
A blue moon on Halloween is even rarer. The next time we’ll see that is in 2039.
We also see full moons in 2020 on Sept. 2, Nov. 30 and Dec. 29. Mark your calendars and look up at the night sky if you want to enjoy them!