look out your window and say hi to the mooN.
The Farmers' Almanac defined blue moon as an extra full moon that occurred in a season; one season was normally three full moons. If a season had four full moons, then the third full moon was named a blue moon.
Using the Farmers' Almanac definition of blue moon (meaning the third full moon in a season of four full moons), blue moons occur
- November 21, 2010
- August 21, 2013
- May 21, 2016
Recent popular usage defined a blue moon as the second full moon in a calendar month, stemming from an interpretation error made in 1946 that was discovered in 1999. For example, December 31, 2009 was a blue moon according to this usage.
Two full moons in one month:
- 2009: December 2, December 31 (partial lunar eclipse visible in some parts of the world), only in time zones west of UTC+05.
- 2010: January 1 (partial lunar eclipse), January 30, only in time zones east of UTC+04:30.
- 2010: March 1, March 30, only in time zones east of UTC+07.
- 2012: August 2, August 31
- 2015: July 2, July 31
do you consider tonight as a blue moon or noT? i'm team farmer's almanac.