Despite the name, the "Blue Moon" won't actually be blue. In fact, it will look the same as any other full moon. According to the current definition, the term refers to the second full moon in a given calendar month. The traditional definition of a Blue Moon was reserved for the third full moon in a season that has four full moons, which happens in years that have 13 full moons instead of the usual 12.
The next seasonal Blue Moon will happen on May 18, 2019, but per the newer definition of the term, the next monthly Blue Moon won't occur until Oct. 31, 2020. The last Blue Moon was an extra special one, as it coincided with a "supermoon" and a total lunar eclipse. [In Photos: The Super Blue Blood Moon Eclipse of 2018]
Today's full moon, which is the first full moon of spring, is also known as a "Paschal Moon," which is the full moon right before Easter Sunday. It has also been nicknamed the "Sap Moon" by Native American tribes "as it marks the time when maple sap begins to flow and the annual tapping of maple trees begins," according to the Old Farmer's Almanac.
Today, the moon will reach its fullest phase at 8:37 a.m. EDT (1237 GMT). For viewers in the eastern United States, the moon will be below the horizon at this time, while those on the West Coast will be able to see it early in the morning.
If the full moon is below the horizon from your location, don't worry. It will still look full when it rises again later in the evening. You can find out exactly when the moon rises and sets at your location with this calculator at timeanddate.com.
If you can't see the Blue Moon for yourself, you can tune into a webcast from Slooh's online observatory, which will feature live views of the Blue Moon and commentary from Slooh astronomers.
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