The only Blue Moon of 2027 is a seasonal Blue Moon at 6:59 a.m. EDT (10:59 UTC) on Thursday, May 20. 2027 has no monthly Blue Moon; the next falls on Sunday, December 31, 2028.
“Blue Moon” has two meanings, and 2027 has only one of them. The May 20 full moon is a seasonal Blue Moon, the third of four full moons in spring 2027. There is no monthly Blue Moon, the second full moon in a calendar month, because each of 2027’s 12 full moons falls in a different month.
Monthly Blue Moons also depend on your time zone: Datescal’s calculations show the December 31, 2028, Blue Moon does not happen in New Zealand, which gets two Blue Moons in early 2029 instead.
This page gives the 2027 Blue Moon time in every US time zone, explains both definitions and where they came from, and lists every Blue Moon from 2026 to 2031.
Table of Contents
When is the Blue Moon 2027?
The 2027 Blue Moon is full at 10:59 UTC on Thursday, May 20, 2027, according to the U.S. Naval Observatory. Moonblink gives 10:58:52 UTC. The table below converts it to US and international time zones.
| Time zone | Blue Moon 2027 (exact full moon) |
|---|---|
| UTC | Thursday, May 20, 10:59 a.m. |
| US Eastern | Thursday, May 20, 6:59 a.m. EDT |
| US Central | Thursday, May 20, 5:59 a.m. CDT |
| US Mountain | Thursday, May 20, 4:59 a.m. MDT |
| US Pacific | Thursday, May 20, 3:59 a.m. PDT |
| Alaska | Thursday, May 20, 2:59 a.m. AKDT |
| Hawaii | Thursday, May 20, 12:59 a.m. HST |
| London | Thursday, May 20, 11:59 a.m. BST |
| India | Thursday, May 20, 4:29 p.m. IST |
| Sydney | Thursday, May 20, 8:59 p.m. AEST |
Because it is a seasonal Blue Moon, the May 20, 2027, full moon is a Blue Moon everywhere in the world, even in the few places where the date falls on May 19 or May 21.
The season’s boundaries are single instants, the March equinox and the June solstice, so the count of full moons in the season is the same in every time zone.
In the United States, the best evenings to see it are Wednesday, May 19, when the 99%-lit Moon rises just before sunset, and Thursday, May 20, when it rises 46 to 51 minutes after sunset in New York, Chicago, Denver, and Los Angeles, according to the Naval Observatory times on the Flower Moon page.
Why May 20 is the Blue Moon
Spring 2027 runs from the March equinox at 4:25 p.m. EDT on Saturday, March 20, to the June solstice at 10:11 a.m. EDT on Monday, June 21.
It holds four full moons instead of the usual three:
| Spring 2027 full moon | US Eastern Time | Name |
|---|---|---|
| 1st | Monday, March 22, 6:44 a.m. EDT | Worm Moon |
| 2nd | Tuesday, April 20, 6:27 p.m. EDT | Pink Moon |
| 3rd | Thursday, May 20, 6:59 a.m. EDT | Flower Moon, the Blue Moon |
| 4th | Friday, June 18, 8:44 p.m. EDT | Strawberry Moon |
Under the seasonal rule the third of the four full moons, not the fourth, is the Blue Moon. EarthSky calls this “weird” but notes that it is the rule; timeanddate.com says the arrangement helps align the church calendar with the Moon’s phases, so that Lent and Easter fall at their proper times.
Seasonal and monthly Blue Moons: two definitions
Seasonal Blue Moon: the third full moon in an astronomical season that has four. According to Wikipedia, this is the original rule, used by the Maine Farmers’ Almanac in the 1930s.
Monthly Blue Moon: the second full moon in a single calendar month. Wikipedia explains that this definition came from a misreading. In the March 1946 issue of Sky & Telescope, James Hugh Pruett interpreted the almanac’s rule as “this second in a month,” and the monthly meaning spread from there. In 1999, Donald Olson, Richard Fienberg and Roger Sinnott worked out the original almanac rule and named it the seasonal definition.
| Seasonal Blue Moon | Monthly Blue Moon | |
|---|---|---|
| Rule | Third full moon in a season with four | Second full moon in a calendar month |
| Origin | Maine Farmers’ Almanac, 1930s | Sky & Telescope misreading, 1946 |
| Depends on time zone? | No | Yes |
| In 2027 | Thursday, May 20 | None |
| Next after 2027 | Thursday, August 23, 2029 (August 24 in UTC) | Sunday, December 31, 2028 |
Wikipedia gives the average gap between monthly Blue Moons as about 2.7 years, or about 32.5 months.
Blue Moon dates for 2026 to 2031
Datescal checked every full moon from 2026 to 2031 in the Naval Observatory’s tables for 2026, 2028, 2029, 2030 and 2031 against each month and each season, with equinox and solstice times calculated with the Astropy astronomy software library. The 2026, 2027, 2028, and 2029 dates match EarthSky’s list.
| Date (US Eastern Time) | UTC | Type | Note |
|---|---|---|---|
| Sunday, May 31, 2026, 4:45 a.m. EDT | May 31, 08:45 | Monthly | Second full moon of May 2026 |
| Thursday, May 20, 2027, 6:59 a.m. EDT | May 20, 10:59 | Seasonal | The only Blue Moon of 2027 |
| Sunday, December 31, 2028, 11:48 a.m. EST | Dec 31, 16:48 | Monthly | New Year’s Eve; brings a total lunar eclipse |
| Thursday, August 23, 2029, 9:51 p.m. EDT | Aug 24, 01:51 | Seasonal | Third of four full moons in summer 2029 |
| Tuesday, September 30, 2031, 2:58 p.m. EDT | Sep 30, 18:58 | Monthly | Also the 2031 Harvest Moon |
2030 has no Blue Moon of either kind. The September 30, 2031, full moon is both a monthly Blue Moon and the Harvest Moon, since it is the full moon nearest that year’s September equinox, as listed on Datescal’s Harvest Moon 2027 page.
The New Year’s Eve 2028 Blue Moon eclipse
The December 31, 2028, Blue Moon brings a total lunar eclipse, with greatest eclipse at 16:52 UTC (11:52 a.m. EST) and about 71 minutes of totality, according to Wikipedia.
Wikipedia says it is completely visible over eastern Europe, Asia and Australia, with only partial visibility from western North America. Datescal’s Cold Moon 2027 page covers the December full moons around it.
Monthly Blue Moons depend on your time zone
A full moon falls on different calendar dates in different time zones, so a month can hold two full moons in one country and one in another. Datescal converted each full moon from 2026 to 2031 into local time to find the monthly Blue Moons in five places:
| Place | Monthly Blue Moons, 2026 to 2031 (local date) |
|---|---|
| US Eastern and Pacific time | May 31, 2026; December 31, 2028; September 30, 2031 |
| Hawaii | May 30, 2026; December 31, 2028; August 31, 2031 |
| India | May 31, 2026; December 31, 2028; October 30, 2031 |
| New Zealand | May 31, 2026; January 30, 2029; March 30, 2029; October 30, 2031 |
| UTC | May 31, 2026; December 31, 2028; September 30, 2031 |
In New Zealand, the December 31, 2028, full moon falls on January 1, 2029, so December 2028 has no Blue Moon there, but January and March 2029 both get one.
In Hawaii, the September 1, 2031, full moon falls late on August 31, which makes August, not September, the Blue Moon month. Wikipedia makes the same point about the 2028 New Year’s Eve Blue Moon, which it says occurs only in time zones west of UTC+08.
Can the Moon actually look blue?
A Blue Moon in either calendar sense looks like any other full moon. The Moon can look blue, but only after events that fill the air with particles of a very particular size.
According to Wikipedia, the Moon appeared blue and green for months after the 1883 eruption of Krakatoa, and on September 23, 1950, smoke from forest fires in Canada made the Moon look blue across eastern North America and Britain.
The particles have to be slightly wider than the wavelength of red light, about 0.7 micrometres, so that they scatter red light and let blue light through.
What a Blue Moon is not
Several terms are confused with the Blue Moon. The table below sets out the differences.
| Term | What it means | Relation to the 2027 Blue Moon |
|---|---|---|
| Seasonal Blue Moon | Third full moon in a season with four | May 20, 2027 |
| Monthly Blue Moon | Second full moon in a calendar month | None in 2027 |
| Black Moon | An extra new moon in a month or season | August 31, 2027, under the monthly definition, on Datescal’s Moon Phases 2027 page |
| Blood Moon | A Moon turned red in a total lunar eclipse | None in 2027; the December 31, 2028, Blue Moon brings one |
| Supermoon | A full moon near the Moon’s closest point to Earth | No; the 2027 supermoon is January 22 |
| A blue-coloured Moon | The Moon looking blue through smoke or volcanic ash | Not related to the calendar Blue Moon |
Frequently asked questions
When is the Blue Moon in 2027?
The 2027 Blue Moon is on Thursday, May 20, at 6:59 a.m. EDT (10:59 UTC), according to the U.S. Naval Observatory. It is a seasonal Blue Moon, the third of four full moons in spring 2027, according to EarthSky and timeanddate.com. It is also May’s Flower Moon.
Is there a monthly Blue Moon in 2027?
No. A monthly Blue Moon is the second full moon in a calendar month, and in 2027 each of the 12 full moons falls in a different month. The most recent monthly Blue Moon was on Sunday, May 31, 2026, and the next is on Sunday, December 31, 2028.
When is the next Blue Moon after 2027?
The next Blue Moon after May 20, 2027, is a monthly Blue Moon on Sunday, December 31, 2028, at 11:48 a.m. EST (16:48 UTC), which also brings a total lunar eclipse. The next seasonal Blue Moon is on Thursday, August 23, 2029, at 9:51 p.m. EDT, which is August 24 in UTC.
Why is it called a Blue Moon?
The calendar meaning comes from the Maine Farmers’ Almanac, which in the 1930s called the third full moon of a four-full-moon season a Blue Moon, according to Wikipedia. A 1946 Sky & Telescope article misread that rule as the second full moon in a month, creating the monthly definition now in wide use.
Does a Blue Moon look blue?
No. A calendar Blue Moon looks like any other full moon. The Moon can look blue after volcanic eruptions or large fires put particles of the right size into the air, as after the 1883 Krakatoa eruption and the Canadian forest fires of September 1950, according to Wikipedia.
How often does a Blue Moon happen?
Wikipedia gives the average gap between monthly Blue Moons as about 2.7 years. From 2026 to 2031, there are three monthly Blue Moons in US time zones, on May 31, 2026, December 31, 2028, and September 30, 2031, and two seasonal Blue Moons, on May 20, 2027, and August 23, 2029.
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