According to information from NASA Earth and the Old Farmer’s Almanac, the last time a full moon fell on Halloween was in 1944.
The rare All Hallows’ Eve full moon follows the harvest moon on Oct. 1. A blue moon is when two full moons fall in the same month.
“When you look at the full moon on Halloween night, it won’t appear blue in color but you’ll be looking at something pretty uncommon,” according to the Farmers’ Almanac. “A full Moon on Halloween occurs roughly once every 19 years.”
The next time a full moon falls on Halloween isn’t expected until 2039, NASA said.
Saturday’s blue moon will peak at 10:49 a.m. ET, but will look full the night before and the night after.
The Halloween full moon will also be a hunter’s moon, which is the first full moon to follow the harvest moon.