When someone says it happens once in a blue moon, it’s a common way to say that something doesn’t happen very often.  You might have heard that a blue moon actually means the second full moon in a calendar month, and if you look up in the sky around 18:00 on July 31, you will be able to see the second full moon this month.

This will not happen again for the next three years. The phrase has nothing to do with the actual colour of the moon.

Interesting facts about a blue moon:

Thought to be called “blue” after an old English term meaning “betrayer,” a blue moon is an extra full moon that occurs in that span, due to a quirk of the calendar.

By the Pruett definition, New Year’s Eve will fall on a blue moon in 2028, coinciding with a total lunar eclipse. The last New Year’s Eve blue moon happened in 2009.

In 1999 there were two full moons in both January and March, but no full moon at all in February. Full moons are supposed to occur once every month.

Moon phrases include “over the moon” (delighted), “to moon over” (thinking about someone), and “shoot for the moon” (to be very ambitious).

Other interesting facts:

Did you know that in September there will be a partial solar eclipse. During this time the moon covers only parts of the sun, as seen from Mbombela. There are no locations on earth where the sun appears completely covered during this event.

Lavender sun is a phenomenon where the sun looks to be lavender or blue in colour, is also caused by clouds of ash scattering certain wavelengths of light, similar to a blue moon.