It's the first time this is happening from 1871 and only the fourth from 1900.
On very rare occasions the moon can actually sport a bluish tint due to atmospheric conditions caused by forest fires or volcanic eruptions. It’s even happened fairly recently. The moon was a little blue across many sections of eastern North America in September 1950, because of smoke from widespread forest fires in western Canada.
Also, after the massive eruption of Mount Pinatubo in the Philippines in June 1991, there were many sightings of a physically blue moon all around the world.
Fortunately these calamities don’t happen that often, and that lends itself to the creation of the phrase “once in a blue moon.”
The astronomical definition of a blue moon has nothing to do with the moon having a tinge of the color blue, nor does it mean that our lunar friend is sad. It all has to do with mathematical odds.
The synodic period of the moon, is 29.5 days. That’s the time it takes the moon to go through all its phases as it goes from evening crescent to full stage and back to morning crescent.
That means we have a full moon every 29.5 days, and since the average length of a calendar month is little over 30 days, it’s bound to happen that we’ll have two full moons in one month every now and then.
On average, we have a blue moon about every year an a half. To experience a blue moon in any given month is a rarity for sure, but to have one New Year’s Eve is even more special
No one really knows exactly when the term blue moon originated. In literature and print it first showed up around 1600 in England, during the time of William Shakespeare.
It wasn’t defined as it is today as the second full moon in a calendar month, but rather a visibly appearing blue moon, with a little imagination and possibly some added paranoia.
Many believed it was a bad omen of global calamities in the near future. A blue moon’s real or imagined appearance even interfered with a scheduling of church festivals and feast days.
A blue moon was also seen as a symbol of sadness and loneliness. Music of the past century reflected this in songs like “Blue Moon,” written in 1934 by Richard Rodgers and Lorenz Hart and recorded by tons of artists.
This year's Blue Moon, though, will mean New Year's Eve will have something special — a full moon that is often attributed to wackier than usual behavior among revelers.
"We joke about it," said a San Jose Police Department dispatcher. But, she added, "It's an urban myth."
The exception, of course, is February, Weinrich points out. Even in a leap year, it only has 29 days.
A blue moon happens roughly every two years. Rarely, one year will have two blue moons.
The last New Year’s Eve blue moon happened in 1990, and the next will be in 2028, according to a Web site maintained by David Harper, who holds doctorates in astronomy and mathematics. His site, www.obliquity.com, includes a blue moon calculator.