What is a Blue Moon and When is The Next One?

Around this New Year's Eve, there will be a blue moon in the sky. Not literally blue; there's going to be some sort of phenomenon called blue moon.
What exactly are they talking about when they say blue moon and when is the next one?

A blue moon isn't actually blue—as commonly defined, the name reflects the relative rarity of two full moons in a month and is linked to the saying "once in a blue moon."

With this New Year's Eve blue moon, there is nothing scientific about it, and it has no astronomical significance.

What's more, this New Year's Eve, people living in the Far East will see a lunar eclipse, making this an even rarerer rarity. A blue-moon eclipse only happens once roughly every 15 to 20 years.

When is The Next One?

In new year's eve.