Moon phases on a printed calendar
The moon is the oldest thing calendars were built around, and it still refuses to fit one neatly: its cycle is 29.53 days, which is why phases drift through the months instead of repeating. This page explains what the symbols on a printed calendar mean, and the one subtlety — time zones — that decides which day a phase belongs to.
The cycle
A lunation runs about 29.53 days (29 days, 12 hours, 44 minutes) from one new moon to the next. Because that is neither four weeks nor a calendar month, each phase arrives roughly a day earlier per month — and some months get the same phase twice. The four principal phases quarter the cycle:
- New moon — the moon stands with the sun; the nights around it are the darkest, which stargazers plan for.
- First quarter — half lit and waxing; rises around midday, sets around midnight.
- Full moon — opposite the sun, up all night.
- Last quarter — half lit and waning; rises around midnight.
A phase is an instant, not a day
A full moon happens at one precise moment, the same moment everywhere on Earth. Whichcalendar day that moment belongs to depends on where you are. A full moon at 23:30 UTC is still that day in London and already the next day in Berlin — both calendars are right, for their readers. Calendarloom prints phases in UTC, the neutral choice; if a phase near midnight matters to you, check it against your own zone.
How Calendarloom computes them
The dates are not looked up — they are computed with the standard algorithms from Jean Meeus's Astronomical Algorithms, including the ΔT correction between Terrestrial Time and UTC. The implementation is validated against an independent list of 213 published perigee full moons spanning 2001–2100, all of which must land on the correct day for the build to pass. The details are on the how it works page.
Full moons of 2026
13 full moons this year (UTC dates):
- January 3
- February 1
- March 3
- April 2
- May 1
- May 31
- June 29
- July 29
- August 28
- September 26
- October 26
- November 24
- December 24
Full moons of 2027
- January 22
- February 20
- March 22
- April 20
- May 20
- June 19
- July 18
- August 17
- September 15
- October 15
- November 14
- December 13
Print them on a calendar
Moon phases are a switch, not a separate product: any layout can carry them. The moon phase calendar page opens the generator with them already on; the daily planner adds moonrise, moonset and illumination for a location you choose.