Moon phase on September 23, 2031

First Quarter, 44%
🌓 First Quarter
Tuesday, September 23, 2031 · at noon (Brasília)
Illumination: 44% Age: 6.8 days Cycle: 23%

On Tuesday, September 23, 2031 the Moon will be in its first quarter phase, with 44% of its disk illuminated and an age of 6.8 days since the last new moon. Half of the disk is lit, about a week after the new moon. The Moon is easy to see in the early evening and sets around midnight.

Moon data for this date

Moon at noon Brasília time (UTC-3)
Phase🌓 First Quarter
Illumination44%
Moon age6.8 days
Day of the weekTuesday
Last new moonSeptember 16, 2031 at 15:47
Next full moonSeptember 30, 2031 at 15:58 (in 7.2 days)
Next new moonOctober 16, 2031 at 05:21 (in 22.7 days)

The Moon on the surrounding days

Compare the phase and illumination over the three days before and after. Click a day to open its page.

← September 22, 2031 September 24, 2031 →

About the first quarter

Half of the disk is lit, about a week after the new moon. The Moon is easy to see in the early evening and sets around midnight. The phase name comes from the Moon's position in its 29.53-day cycle: on September 23, 2031 it had completed 23% of the cycle that began with the new moon on September 16, 2031.

Looking for another date, such as a birthday? Use the Moon phase on the day I was born tool, see the Moon phase today page with the lunar calendar, or find the day of the week of September 23, 2031. For sun times, check sunrise and sunset.

Frequently asked questions

What is the Moon phase on September 23, 2031?

On September 23, 2031 the Moon will be in its first quarter phase, with 44% of the disk lit (calculated at noon Brasília time).

How old is the Moon on that date?

The age is the time since the last new moon: 6.8 days of an average 29.53-day cycle.

When is the next full moon after that date?

The next full moon after September 23, 2031 falls on September 30, 2031 at 15:58 Brasília time.

When is the next new moon after that date?

The next new moon after September 23, 2031 falls on October 16, 2031 at 05:21 Brasília time.

How is the Moon phase calculated?

With Jean Meeus's astronomical formulas for the instants of new, quarter and full moon. The age comes from the time since the last new moon and the illumination is (1 − cos(2π × cycle fraction)) / 2.

Is the phase the same everywhere in the world?

Yes, the phase and the illuminated percentage are the same across the planet at any given instant. Only the orientation changes: in the southern hemisphere a waxing Moon is lit on the left, in the northern one on the right.