It's called a "Black Moon," and it hasn't happened in 19 years.
That's because a full moon will not be visible in February for the first time this century.
December 2017, for example, saw the first of three super moons (when the moon is at its closest to Earth, so it appears slightly larger than usual in the evening sky). Then in January, there were two super full moons, the latter of which is called a blue moon because it was the second full moon in a single month. By chance, it also happened to coincide with a total lunar eclipse, which turned our satellite a deep red color.
Why Is There No Full Moon in February?
At 28 days (and still only 29 days every fourth leap year), February is the shortest calendar month. It takes 29.53 days for the moon to orbit Earth –– a so-called synodic month –– so if there's a full moon on January 31, there cannot be another until March 1.
And that's exactly what's happening this year. A February "Black Moon" occurs about four times per century.
What Is the Full Moon Called in February?
Typically, full moons in February are called Snow Moons, named for the winter snow (usually) blanketing the ground. Some North American tribes also called it the hunger moon and the storm moon.
But because of the lunar cycle, there will not be a snow moon in 2018.
Moon-gazers, however, should not feel shortchanged. The moon's ever-changing phases are the same as always, and a beautiful, thin crescent moon will be visible in the west after sunset on February 16, 17, and 18.
By February 28, the moon will be 97 percent illuminated — almost full to the untrained eye. The following day will be March's full Worm Moon, named for the seasonal return of earthworms to the ground in North America. It will be officially full at 7:51 p.m., Eastern Standard Time.
When Was the Last Time February Had No Full Moon?
This phenomenon last occurred in 1999 (when it was also preceded by a blue blood moon eclipse) and, before that, in 1980 and 1961.
It works out that every 19 years, there is no full moon during the month of February. This 19 year cycle is called the Metonic Cycle, which sees the exact phase of the moon occurring on more or less the same date at 19 year intervals.
Whenever there is no full moon in February, both January and March have two full moons each — the second of which is popularly called a blue moon.
When Is The Next February Black Moon?
According to the Metonic Cycle, 2037 will be the next time February has no full moon. That year, both January and March will contain two full moons each. Just as in 2018, the second full moon in January 2037 will be a super blue blood moon eclipse.
Even more rare than this February's black moon is when there is no full moon in a 29-day February, during a leap year. That last happened in 1608, and won’t happen again until 2572.