Have you ever said something happens only once in a blue moon? Well, that event may happen sooner than you think.
In fact, we have 2 full moons on tap for the month of August and the blue moon is set to be the second of the two. The the first arrives tomorrow night, on August 1st, that's the first full moon. The blue moon is the 2nd of the two and will take place on August 31st.
The full moon that night will probably look no different than any other full moon, but the moon can change color in certain conditions. After forest fires or volcanic eruptions, the moon can appear to take on a bluish color because soot and ash particles in the sky can sometimes make the moon appear bluish.
In the aftermath of the massive eruption of Mount Pinatubo in the Philippines in June 1991 there were reports of blue moons worldwide.
This doesn't happen every month as the next blue moon won't arrive until July 2015. You'll have to wait 3 years if you miss this one on the 31st.