Tonight there will be a blue moon but what does that term really even mean? Here is some information to help you understand.

The blue moon will not actually be blue. It will look like any other full moon.

A blue moon is the second full moon in a calendar month. July had it’s first full moon on the Tuesday the 2nd.

The last blue moon occurred on August 31st, 2012. After tonight’s, the next blue moon won’t happen until January 31st, 2018.

Hundreds of years ago, the phrase ‘Once in a blue moon’ just meant rare or absurd and had nothing to do with the actual moon.

The modern definition of the blue moon has only been around since the 1940s. James Hugh Pruett created the defined the modern blue moon in the magazine ‘Sky and Telescope’ in 1946.

Sometimes the moon actually does look blue. This is caused by particles in the atmosphere from events such as volcanic eruptions and forest fires. For example, in 1843 the eruption of Krakatoa caused people in Indonesia to see blue moons nearly every night for two years. This type of blue moon is completely unrelated to the one tonight.

The blue moon will rise tonight between 8pm and 8:30pm depending on your location in the world. 9