Saturday's blue moon will be the last one until 2020

Saturday's blue moon will be the last one until 2020

Double blue-moon years are relatively rare, with the last occurring in 1999, and the next in 2037.

This isn't just the second full moon in the month (what makes it a "blue" moon) but also the second Blue Full Moon of the year! The blue moon will travel through the night's sky before setting early in the morning on Saturday, March 31.

A blue moon does not actually appear blue, but is so named because it is the second full moon in a calendar month and only happens occasionally. As blue moons typically occur once every two to three years, we will not see another one until Halloween night on October 31, 2020.

Blue Moon 2018 Spiritual meaning and superstitions
GETTYBlue Moon 2018 Astrologers believe the Blue Moon is supercharged with lunar energy

When blue moons do occur twice in a year, it is usually in January and March because of February being 28 days.

An airplane flies in front of the Blue Moon of July 31, 2015, in this photo captured by skywatcher Chris Jankowski of Erie, Pennsylvania. Smoke and dust within the atmosphere can cause the moon to take on a blueish tint.

For people looking to catch the "once in a blue moon" event this Easter weekend, the moon will rise Friday night on March 30.

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