Moon phase on July 21, 1981

Waning Gibbous, 73%
🌖 Waning Gibbous
Tuesday, July 21, 1981 · at noon (Brasília)
Illumination: 73% Age: 19.8 days Cycle: 68%
Home → Moon phase → July 21, 1981

On Tuesday, July 21, 1981 the Moon was in its waning gibbous phase, with 73% of its disk illuminated and an age of 19.8 days since the last new moon. The lit part starts to shrink. The Moon rises a few hours after dusk and is still in the sky when day breaks.

Moon data for this date

Moon at noon Brasília time (UTC-3)
Phase🌖 Waning Gibbous
Illumination73%
Moon age19.8 days
Day of the weekTuesday
Last new moonJuly 1, 1981 at 16:04
Next full moonAugust 15, 1981 at 13:37 (in 25.1 days)
Next new moonJuly 31, 1981 at 00:53 (in 9.5 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.

SatJul 18Waning Gibbous, 95%95%Waning GibbousSunJul 19Waning Gibbous, 89%89%Waning GibbousMonJul 20Waning Gibbous, 82%82%Waning Gibbous
TueJul 21Waning Gibbous, 73%73%Waning Gibbous
WedJul 22Waning Gibbous, 63%63%Waning GibbousThuJul 23Last Quarter, 52%52%Last QuarterFriJul 24Last Quarter, 41%41%Last Quarter

← July 20, 1981 July 22, 1981 →

About the waning gibbous

The lit part starts to shrink. The Moon rises a few hours after dusk and is still in the sky when day breaks. The phase name comes from the Moon's position in its 29.53-day cycle: on July 21, 1981 it had completed 68% of the cycle that began with the new moon on July 1, 1981.

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 21, 1981. For sun times, check sunrise and sunset.

Frequently asked questions

What is the Moon phase on July 21, 1981?

On July 21, 1981 the Moon was in its waning gibbous phase, with 73% 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: 19.8 days of an average 29.53-day cycle.

When is the next full moon after that date?

The next full moon after July 21, 1981 falls on August 15, 1981 at 13:37 Brasília time.

When is the next new moon after that date?

The next new moon after July 21, 1981 falls on July 31, 1981 at 00:53 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.