The Moon rises later each day because it moves about 13.2° east along its orbit every day, so Earth must turn a little further each day before your horizon catches up with the Moon. The average delay is about 50 minutes, but at mid-latitudes it ranges from roughly 30 to 70 minutes.
Key facts
- The Moon moves about 13.2° east against the stars each day, and gains about 12.2° a day on the Sun.
- Earth turns 15° an hour relative to the Sun, so catching up with the Moon takes about 50 minutes.
- The delay ranges from about 30 to 70 minutes at mid-latitudes, depending on the angle of the Moon's path to the horizon.
- Around the Harvest Moon the delay shrinks to about 20–30 minutes for several evenings.
How does the Moon’s orbit make moonrise later?
The Moon orbits Earth in the same direction that Earth spins, from west to east, so each day the Moon has moved ahead and Earth needs extra rotation to bring it back to your horizon.
The Moon completes one orbit against the stars in 27.32 days, about 13.2° a day. The Sun also drifts about 1° east against the stars each day as Earth travels around it, and our 24-hour clock is set by the Sun. What matters for moonrise is therefore how far the Moon pulls ahead of the Sun: about 12.2° a day, one full lap every 29.53 days.
This daily step is built into all moonrise and moonset times, and it is also why the phase changes. Each 12.2° step widens or narrows the angle between the Sun and the Moon, so the lunar cycle of phases and the drift of moonrise are two views of the same motion.
Where do the 50 minutes come from?
Earth turns 15° an hour relative to the Sun, so making up the Moon’s daily lead of about 12.2° takes about 49 minutes, plus about 1.6 minutes for the distance the Moon moves in the meantime.
Step by step:
- The Moon’s daily motion against the stars: 360° ÷ 27.32 days ≈ 13.2° a day.
- Minus the Sun’s daily drift: 360° ÷ 365.25 days ≈ 1.0° a day, which leaves the Moon gaining about 12.2° a day on the Sun (360° ÷ 29.53 days).
- Earth’s turn relative to the Sun: 360° ÷ 24 hours = 15° an hour, or 1° every 4 minutes.
- Time to turn 12.2°: 12.2 × 4 minutes ≈ 49 minutes.
- The Moon keeps moving: in those 49 minutes it travels about 0.4° further, which takes about 1.6 minutes more.
- Total: about 50.5 minutes, so the lunar day, from one moonrise to the next, lasts about 24 hours and 50 minutes on average.
- Moon's motion against the stars
- about 13.2° per day
- Moon's gain on the Sun
- about 12.2° per day
- Earth's turn relative to the Sun
- 15° per hour (1° every 4 minutes)
- Average lunar day
- 24 h 50 min
- Daily delay at mid-latitudes
- about 30 to 70 minutes
In practice, if the Moon rises at 7:00 p.m. on a Monday, the average delay puts the next moonrises near 7:50 p.m. on Tuesday and 8:40 p.m. on Wednesday. Over one 29.5-day cycle these daily steps add up to a full 24 hours, so moonrise comes back to about the same time of day at the same phase.
Why isn’t the delay always 50 minutes?
The delay changes because the Moon’s path meets the eastern horizon at different angles: a shallow path brings the Moon up sooner, and a steep path brings it up later.
The Moon travels close to the ecliptic, the Sun’s path across the sky, and the angle the ecliptic makes with the horizon changes through each orbit. When the angle at moonrise is shallow, much of the Moon’s daily step runs along the horizon, carrying the Moon northward rather than downward, so the Moon rises sooner than average. When the angle is steep, the whole step has to be made up and the Moon rises later.
As seen from the Northern Hemisphere, the angle at moonrise is shallowest when the Moon is near the March equinox point, among the stars of Pisces, and steepest when it is near the September equinox point, in Virgo. The Moon passes both points every month, so short and long delays come every month, at whatever phase happens to be there. In the Southern Hemisphere the pattern is reversed.
A smaller effect comes from the Moon’s changing speed. The Moon moves faster near perigee, its closest point to Earth, than near apogee, which adds or removes a few minutes. Together these effects give delays from about 30 to 70 minutes at mid-latitudes.
What is the Harvest Moon effect?
The Harvest Moon effect is the run of evenings around the full moon nearest the September equinox when the Moon rises only about 20–30 minutes later each night instead of the usual 50.
A full moon sits opposite the Sun. In September the Sun is near the September equinox point, so the full moon is near the March equinox point in Pisces, exactly where the moonrise delay is shortest. The result is bright moonlight soon after sunset for several evenings in a row, which farmers once used to keep harvesting after dark. The Harvest Moon page lists its upcoming dates.
The Southern Hemisphere has the same effect around its own autumn equinox in March. There, the full moon nearest the March equinox is the one that rises only a little later each evening.
What happens at high latitudes?
The farther you are from the equator, the more extreme the angle of the Moon’s path becomes, so the short delays around the Harvest Moon grow shorter and the long delays half a month later grow longer.
Near the poles the pattern breaks down. The Moon cannot set when its angle north of the celestial equator is greater than 90° minus your latitude. Above about 72° latitude that happens for several days every month, and in years near a major lunar standstill, most recently around December 2024, down to about 61.5°. During those days the Moon circles the sky without setting, and about two weeks later it stays below the horizon, so there is no moonrise at all for a stretch of days.
At ordinary latitudes, the 50-minute drift also explains why the Moon spends so many days rising in daylight, which is why you can see the moon during the day. For the rise and set times at your own latitude, check the Moon tonight.