Moon over Mt. Shasta: full moon will be visible Halloween night for first time in decades
- The last time that a full moon was seen in all U.S. time zones on Halloween was 1944.
- The Halloween full moon is also known as a "blue" moon because it's the second full moon of the month.
- The moon won't appear blue on Halloween night. It will be the same color it's always been.
Halloween night will feature the moon event of the year.
For the first time in decades, there will be a full moon visible across the entire U.S. on Halloween night, Oct. 31.
The last time that a full moon was seen in all U.S. time zones on Halloween was 1944, according to the Farmers' Almanac. The next time we’ll see an equally spooky Halloween full moon is 2039, so plan your werewolf costumes accordingly.
The Halloween full moon is also known as a "blue" moon because it's the second full moon of the month.
Usually months have only one full moon, but occasionally a second one sneaks in, NASA said. Full moons are separated by 29 days, while most months are 30 or 31 days long; so it is possible to fit two full moons in a single month.
This happens every 2½ years, on average.More:Water discovered on sunlit part of the moon for the first time, NASA says
Fun fact: Every full moon on Halloween is a blue moon because moon cycles are 29.5 days long and Halloween is always on Oct. 31.
(There is an alternate definition of a blue moon: When there are four full moons in a single season, the third is considered a blue moon, the Farmers Almanac said.)
Of course, the moon won't appear blue on Halloween night. It will be the same color it's always been.
Blue-colored moons in photos are usually made using special blue camera filters or in a post-processing program such as PhotoShop, according to Earthsky.org. But there are rare occasions when a moon does take on a bluish hue, CNN reports.
Smoke or dust particles in the atmosphere, such as during a major volcanic eruption, can result in a blue-looking moon.
In addition to being called a blue moon, Halloween's full moon is also called the Hunter's moon. "Many moons ago, Native Americans named this bright moon for obvious reasons," the Farmer's Almanac said. "The leaves are falling from trees, the deer are fattened, and it’s time to begin storing up meat for the long winter ahead."
The first full moon of the month, on Oct. 1, was known as the Harvest moon.