Wondering when the next blue moon will occur? Here’s a list of the upcoming blue moons through 2029 along with a look back to the blue moons since 2010.
What is a blue moon?
We typically refer to a blue moon as two full moons occurring in the same month. While we think that about the saying “once in a blue moon” as a very rare occurrence, it’s a little more frequently than you realize when you watch the calendar.
How often do blue moons occur?
Generally, a blue moon only occurs about every 2 and a half years. Usually, in the year that a blue moon occurs, there is only 1, but sometimes there are two such as in 2018.
Blue Moons in 2018, a year worth noting
2018 was an unusual blue moon year because two blue moons occurred at the start of the year, in January and March. As a result, February did not have a full moon at all. The lack of a full moon in a month is sometimes referred to as a black moon.
The Seasonal Blue Moon, another blue moon definition
A seasonal blue moon is the third blue moon in an astronomical season when four full moons occur within the season (Spring, Summer, Fall, and Winter). This definition is less commonly used for the blue moon because you need to look closer at the full moon cycles from December of the prior year through December of the fulling year as each winter crosses two calendar years. Astronomical seasons begin with the solstices and equinoxes each year.
The solstices, referred to as the longest or shortest day of the year, means the amount of daylight for that day. Equinoxes are when the light and dark parts of the day are the same length (equal).
- Spring starts with the spring equinox
- Summer begins with the summer solstice
- Fall starts on the fall equinox
- Winter begins with the winter solstice
The spring equinox is usually March 19th or 20th each year and the summer solstice is around June 20th or 21st. The fall equinox occurs on September 22nd or 23rd and the water solstice is usually on December 21st or 22nd each year.
When is the next blue moon?
There are 4 calendar blue moons coming up between now and 2027 along with 3 seasonal blue moons.
Now that the Halloween Full Blue Moon of 2020 has come and gone, the next blue moon will be a seasonal blue moon on Sunday, August 22, 2021 08:02 EST or 13:02 UTC.
The next calendar blue moon is Friday, August 30, 2023 21:35 EST or August 31, 2023 02:35 UTC.
The dates and times are provided by NASA in Eastern Standard Time (EST) with Daylight Saving Time (DST) for part of the year. Also below is the Universal Time Coordinated (UTC) time. This was previously referred to at Greenwich Mean Time (GMT).
| Year | Month | Blue Moon Dates | UTC Time |
|---|---|---|---|
| 2021 | August | Sunday, August 22, 2021 08:02 EST (seasonal) | 13:02 UTC |
| 2023 | August | Friday, August 30, 2023 21:35 EST | 02:35 UTC (August 31, 2023) |
| 2025 | December | December 4, 2025 18:14 EST (seasonal) | 23:14 UTC |
| 2026 | May | Sunday, May 31, 2026 04:45 EST | 09:45 UTC |
| 2027 | May | Thursday May 20, 2027 06:59 EST (seasonal) | 11:59 UTC |
| 2029 | August | Thursday, August 23, 2029 21:51 EST (seasonal) | 02:51 UTC (August 24, 2029) |
And when was the last blue moon?
The last blue moon occurred on October 31, 2020 9:49 Eastern Time. It was the only blue moon in 2020.
Looking back from 2020 to 2010, there were 8 blue moons, and two of them were in 2018. 2018 was also an interesting year because February did not have a full moon (sometimes called a black moon).
Blue moons did not occur in 2010, 2011, 2015, or 2017.
| Year | Month | Day of the week | Past Blue Moons |
|---|---|---|---|
| 2020 | October | Saturday | October 31, 2020 09:49 EST |
| 2019 | May | Saturday | May 18, 2019 17:11 EST (seasonal) |
| 2018 | January | Wednesday | January 31, 2018 08:27 EST |
| 2018 | March | Saturday | March 31, 2018 08:37 EST |
| 2015 | July | Friday | July 31, 2015 06:43 EST |
| 2012 | August | Friday | August 31, 2012 09:58 EST |
