How often do lunar eclipses and blue moons occur simultaneously

This happened on my birthday, december 31, in 2009. i was wondering if this is something id live to see again?

Warning: these are all very vague and approximate back-of-the-envelope calculations. There is a great deal of inaccuracy here.

Lunar eclipses happen about twice a year. Thus about one in every six full moons is a lunar eclipse.

If by "blue moon" you mean a second full moon in a calendar month, about one in every 32 full moons is a blue moon.

This suggests that about one in every 192 full moons is both a blue moon and a lunar eclipse. Thus one would expect this to happen about every 16 years. So unless you're quite elderly now, it's nearly certain that the combination of a lunar eclipse and a blue moon on the same day would happen again in your lifetime.

But you also said it happened on your birthday, so you're only looking at 1/365 of those full moons. So a combination lunar eclipse/blue moon will only occur on your birthday about one in every 70000 full moons, or once in around 5833 years. Very unlikely to occur again in your lifetime.

On the other hand, I'm ridiculously sleep-deprived at the moment, so I may have made a mistake in there somewhere. Take it all with a grain of salt.

Good question, but the answer is hard to find. Most sites I have found just refer to the 2009 one, the astronomy forums just seem to end up arguing about the definition of "blue moon" or miss the point entirely and concentrate only on 31st December.

One site gave a "guesstimate" of about once every 6 years, but I don't think that is correct.