The Halloween Hunter’s Blue Moon Explained

The moon is having a big month and a big week, really! It was announced on Monday by NASA that water molecules were discovered on the moon. Not only that, October gets bookends of full moons--the first on the first and the second on the 31st.

This weekend's moon gets the fancy name of a hunter's blue moon, and it just happens to be on Halloween. The second full moon in a month is called a blue moon, and it also gets the hunter distinction because it follows the October 1 harvest moon. This term comes from the time when hunting and gathering was the primary form of, well, grocery shopping. Under a harvest moon, the people collected the last of the early fall crops, and under the hunter's moon, hunters took to the plains and the woods to stock up on meat for winter.

Now to the Halloween of it all. According to our friends at NASA, there is a full moon on Halloween approximately every 19 years. So that means, including Saturday, we get four more full moons on Halloween before the turn of the next century. The moon's cycle and Halloween haven't synced up since 1944, which was the last time a full moon graced the sky on an all hallow's eve. That is one scary thought.

Lastly, if the blue moon finds you standing alone, the educators at Lowell Observatory in Flagstaff, Arizona have your back. Tune into their live stream on Saturday night, where they talk about the special moon and other scary astronomy.