Moon phase on July 31, 2023

Full Moon, 99%
🌕 Full Moon
Monday, July 31, 2023 · at noon (Brasília)
Illumination: 99% Age: 13.9 days Cycle: 47%

On Monday, July 31, 2023 the Moon was in its full moon phase, with 99% of its disk illuminated and an age of 13.9 days since the last new moon. The whole disk is lit: the Moon rises as the Sun sets and stays up all night. It is the brightest and most photographed phase.

Moon data for this date

Moon at noon Brasília time (UTC-3)
Phase🌕 Full Moon
Illumination99%
Moon age13.9 days
Day of the weekMonday
Last new moonJuly 17, 2023 at 15:31
Next full moonAugust 1, 2023 at 15:31 (in 1.1 days)
Next new moonAugust 16, 2023 at 06:38 (in 15.8 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.

← July 30, 2023 August 1, 2023 →

About the full moon

The whole disk is lit: the Moon rises as the Sun sets and stays up all night. It is the brightest and most photographed phase. The phase name comes from the Moon's position in its 29.53-day cycle: on July 31, 2023 it had completed 47% of the cycle that began with the new moon on July 17, 2023.

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 July 31, 2023. For sun times, check sunrise and sunset.

Frequently asked questions

What is the Moon phase on July 31, 2023?

On July 31, 2023 the Moon was in its full moon phase, with 99% 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: 13.9 days of an average 29.53-day cycle.

When is the next full moon after that date?

The next full moon after July 31, 2023 falls on August 1, 2023 at 15:31 Brasília time.

When is the next new moon after that date?

The next new moon after July 31, 2023 falls on August 16, 2023 at 06:38 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.