"Once in a blue moon" is an idiom that we've all used at some point, and the meaning is pretty implicit. Most people have never seen a blue moon, so the fact that something might have happened "once" in a blue moon clearly means that it's something that rarely happens. We'll be getting a blue moon tomorrow, but it's more likely to be crimson than cobalt.

The technical definition of a blue moon varies, and according to Time And Date, there are two common takes on the term. The obvious one is an actual blue moon, where the moon actually takes on a cobalt hue. It's super rare, and is most often observed after a forest fire or a volcanic eruption. That's not the kind we're getting tomorrow.

Tomorrow's moon is considered blue because it's the second full moon we'll have seen in the month of July. It's a fairly rare occurrence, but not nearly as unseen as a true blue moon. Nonetheless, depending on where the moon appears in the sky when you're looking, you might get treated to a red moon. This phenomenon occurs for the same reasons as a blue moon (different types atmospheric dust filter out different colors).

Check out the clip below for the full scoop, and when you're done watching, be sure to let us know what you though on Facebook. Make sure you share this with your friends — they won't want to miss it!