Most months have just one full moon, because the 29.5-day cycle of the moon matches up pretty well with the length of calendar months. Occasionally, there will be two full moons in a month, something that happens about every 2½ years, NASA says.
As for the moon actually looking blue: it’s possible, but that’s sometimes caused by fine dirt circulating in the Earth’s atmosphere or the dark blue tone of the sky.
New Year's Eve blue moons are rarer, occurring every 19 years- the next will be in 2028.
Happy Blue Moon New Year to All!