Blue Moon - Frequency by month

Do Blue Moons occur more frequently in some months than others? We looked at all of the Blue Moons for 10,000 years starting with the year 1600, and this is what we found:

Month	Full Moons on 1^st and 30^th	Full Moons on 1^st and 31^st	Full Moons on 2^nd and 31^st	Total
January	156	202	128	486
February				0
March	137	220	119	476
April	147			147
May	169	165	157	491
June	161			161
July	163	179	162	504
August	178	165	168	511
September	181			181
October	174	161	181	516
November	162			162
December	151	199	144	494

The months with 31 days are clearly more likely to have two Full Moons than those with just 30 days. February never sees two Full Moons, because the minimum interval between Full Moons is always greater than the length of that month, even in a leap year.

Once in a Blue Moon

Blue Moon frequency by month