Blue moon: next date
"Blue moon" doesn't mean the Moon looks blue: it's the name given to certain "extra" full moons under two distinct, both real and used, definitions. Here's the next date for each, computed with the same ephemeris used for your birth chart.
Modern definition: the second full moon in a month
The most commonly cited today: when a Gregorian calendar month contains two full moons (possible because a month is longer than the ~29.5-day lunar cycle), the second one is called a blue moon. It's fairly rare: it happens roughly every 2-3 years.
Traditional definition: the third full moon in a season with four
The original definition (Maine Farmers' Almanac): each astronomical season (between one equinox/solstice and the next) usually has three full moons. When it has four, the third one is called a blue moon. It also happens roughly every 2-3 years, but on different dates than the modern definition.
Upcoming blue moons
| Type | Date | Sign | Time (UTC) |
|---|---|---|---|
| Traditional (seasonal) | May 20 2027 | Scorpio | ~12:00 |
| Modern (monthly) | Dec 31 2028 | Cancer | ~17:00 |
| Traditional (seasonal) | Aug 24 2029 | Pisces | ~02:00 |
| Modern (monthly) | Sep 30 2031 | Aries | ~19:00 |
| Traditional (seasonal) | Aug 21 2032 | Aquarius | ~02:00 |
Frequently asked questions
- Does a blue moon actually look blue?
- No. The name has nothing to do with color — it's just the label given to certain "extra" full moons on the calendar. (A bluish tint can occasionally appear, very rarely, from particles in the atmosphere after large wildfires or volcanic eruptions — a separate optical phenomenon unrelated to these dates.)
- When is the next modern (monthly) blue moon?
- The next modern blue moon is on December 31, 2028 in Cancer, around 17:00 UTC.
- When is the next traditional (seasonal) blue moon?
- The next traditional blue moon is on May 20, 2027 in Scorpio, around 12:00 UTC.
This is your sign's general horoscope
Your personalized transit —calculated from your full birth chart, not just your sign— is far more precise.
Calculate my chart free ✦Sources: Modern/monthly definition: popular astronomy usage (origin: Sky & Telescope's 1946 interpretation of the Maine Farmers' Almanac). Traditional/seasonal definition: the Maine Farmers' Almanac (US, 19th-20th c.).
Both dates are computed by comparing the real full moons from the ephemeris engine (same calculation used across the site) against the Gregorian calendar and against the exact boundaries of each astronomical season (equinoxes/solstices, exact hour/minute). Not estimated or copied from a table.