Appearing just once every three years or so, a Blue Moon is commonly known as the second full moon within a calendar month. The first full moon of July appeared on the 2nd, and another will appear in the early morning hours of Friday morning, July 31st. More traditionally, a Blue Moon is the third full moon of four appearing in a single astronomical season.
Despite its name, however, the moon won’t actually appear blue, though certain atmospheric conditions may give it a colorful tinge at different points throughout the year.
This full moon also coincides with the final days of the Delta Aquariid meteor shower, and the timing means the upcoming Perseids will peak in a nearly moonless sky.