Moon phases in September 2031

All 30 days, computed from the ephemeris rather than copied from another calendar: the Moon’s sign, the exact instant it changes sign, and the lit fraction of the disc. Shown in your own timezone.

  • Corn MoonSeptember 18.8° Pisces
  • New MoonSeptember 1623.7° Virgo
  • Harvest MoonSeptember 307.4° Aries

Day by day

The four quarter instants are marked on the day they fall; every other day carries the interval it is in. Four of the eight phases are moments and four are stretches, which is the one thing most calendars leave out.

DatePhaseSignIlluminationNotes
Mon 1Full MoonPisces100%
Tue 2Waning GibbousPisces→Aries98%
Wed 3Waning GibbousAries94%
Thu 4Waning GibbousAries88%
Fri 5Waning GibbousAries→Taurus80%
Sat 6Waning GibbousTaurus71%
Sun 7Waning GibbousTaurus→Gemini61%
Mon 8Last QuarterGemini52%
Tue 9Waning CrescentGemini→Cancer42%
Wed 10Waning CrescentCancer33%
Thu 11Waning CrescentCancer24%
Fri 12Waning CrescentCancer→Leo17%
Sat 13Waning CrescentLeo10%
Sun 14Waning CrescentLeo→Virgo5%
Mon 15Waning CrescentVirgo2%
Tue 16New MoonVirgo0%
Wed 17Waxing CrescentVirgo→Libra1%
Thu 18Waxing CrescentLibra3%
Fri 19Waxing CrescentLibra→Scorpio8%
Sat 20Waxing CrescentScorpio14%
Sun 21Waxing CrescentScorpio→Sagittarius23%
Mon 22Waxing CrescentSagittarius33%
Tue 23Waxing CrescentSagittarius→Capricorn44%
Wed 24First QuarterCapricorn55%
Thu 25Waxing GibbousCapricorn66%
Fri 26Waxing GibbousCapricorn→Aquarius77%
Sat 27Waxing GibbousAquarius86%
Sun 28Waxing GibbousAquarius→Pisces93%
Mon 29Waxing GibbousPisces98%
Tue 30Full MoonPisces→Aries100%

Rows are UTC calendar days. The exact times follow the timezone setting above, so a time close to midnight can belong to the neighbouring day in your own zone.

2
Full moons
1
New moons
13
Sign changes
100%
Brightest night

The Moon passes through 14 signs this month, in order: Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, Pisces, Aries. It changes sign 13 times — roughly every two and a third days, though not evenly, because the Moon’s speed varies about twelve per cent over an orbit.

Two full moons this month

September 2031 carries a full moon on September 1 and another on September 30. The second one is a Blue Moon in the modern, month-based sense — the extra one the twelve traditional names have no slot for. It is not the older seasonal definition, which gives different dates, and nothing about the Moon looks any different.

This month’s full moon is the Harvest Moon

The Harvest Moon is the full moon falling nearest the September equinox — a rule about the sky, not a slot in a month table. That is why it moves between September and October from year to year, and why a calendar that reads the name off a fixed twelve-row list gets it wrong in the years it lands in October.

Frequently asked questions

When is the full moon in September 2031?

There are 2 in September 2031. The exact instants are in the table above, shown in your own timezone, with the degree and sign each one falls on.

When is the new moon in September 2031?

There are 1 in September 2031, listed to the minute in the table above along with every other phase of the month.

What timezone are these times in?

Your own, resolved in your browser. The rows are UTC calendar days, so an instant close to midnight can belong to the neighbouring day once converted — the table marks those with a small +1 or −1. You can switch the whole page to UTC if you want to compare it against a site that publishes UTC.

What sign is the Moon in during September 2031?

It moves through 14 of them, changing sign 13 times. The exact instant of each change is in the sign column above. The Moon spends about two and a third days in a sign, which is why it covers the whole zodiac in a month while the Sun takes a year.