Make sure to step outside tonight at sunset to check out the blue moon. A blue moon occurs when it’s the second full moon of the month, an event that only happens every three or four years. The first full moon was on July 2.
What’s even better, it’s the perfect evening for a full moon, with Environment Canada reporting perfectly clear skies tonight and into the weekend.
A “blue moon” actually has nothing to do with the colour. In fact there is a possibility tonight’s moon will be a very deep red. The term has more to do with how rare it is. Once in a “blue moon” however, a truly blue colored moon can occur, with most being spotted after volcanic eruptions.
“Often, when the Moon is hanging low, it looks red for the same reason that sunsets are red, NASA explains. “The atmosphere is full of aerosols much smaller than the ones injected by volcanoes. These aerosols scatter blue light, while leaving the red behind.”