You've heard of once in a blue moon". That's because this real "blue moon" happens only every 3 years. To define it-it's when 2 full moons happen in the same month.
According to those that know, it may look bluer tonight because of tiny particles, from an unusually active fire season, are flooding the atmosphere. Someone has named it the FLOATING BLUEBERRY!
So, get outside tonight, around 10pm or so, and check it out. There won't be another blue moon until 2018!