15. Halloween Full Moons Are Relatively Rare
A popular and enduring Halloween image is a full circle looming over the landscape, especially if it’s a large, golden harvest moon. Many Halloween-themed movies and television programs include the full lunar look, whether through plot device or showing the starry sky itself. Anyone who has trick-or-treated under a full moon likely remembers the beautiful glow aiding in their nighttime travels. However, despite how fabled the Halloween full moon is, it is a relatively rare occurrence.
The next Halloween with a full moon will occur in 2020. The previous full ones date back to Halloween 2001 and 1955. The entire 21st century will see only six Halloween full moons: 2001, 2020, 2039, 2058, 2077, and 2096. Astronomers have found that the frequency of this phenomenon occurring on a specific date is twice within any 59 year period.
If one wants an infrequent Halloween lunar occurrence, keep your fingers crossed for a Halloween black moon or blue moon. Due to the slight mismatch between the lunar and Gregorian calendars, some months have either two new moons or two full ones. In 2016, October saw two new moons, which is called a black moon. Halloween 2020 will see a blue moon!