Moonrise & Moonset
When the moon rises and sets where you are, for a whole month at a time.
How it works
The moon's position is computed from a reduced form of Meeus' lunar theory, converted to right ascension and declination, and then to an altitude above your horizon. The page scans the day for the moment that altitude crosses −0.833° — the standard horizon allowing for refraction and the moon's apparent size — and narrows each crossing by bisection.
Unlike the sun, the moon does not keep to a daily rhythm: it rises roughly fifty minutes later each day. Over a month that slip adds up to a full day, so about once a month a calendar day has no moonrise at all, or no moonset. Those days show a dash rather than an invented time.
Examples
Planning a night walk. A full moon near the horizon at dusk gives light for most of the night; a waning crescent does not rise until the small hours, leaving the evening genuinely dark.
Photography. Moonrise close to sunset is when a large moon can be framed against a still-lit landscape, which is the shot that needs planning rather than luck.
Understanding a missing day. Scanning a whole month shows the roughly fifty-minute daily slip, and the day each month where the moon does not rise at all before midnight.
Practical notes
The moon rises about fifty minutes later each day, because it moves roughly thirteen degrees along its orbit while the Earth turns. Over a month that slip accumulates through the whole clock, which is why the moon is sometimes a morning object and sometimes an evening one.
A consequence of the slip is that some calendar days have no moonrise and others none at all — the event simply falls past midnight into the next day. That gap in a table is correct rather than missing data.
Times are computed from a reduced lunar position model and are accurate to a couple of minutes for most locations, degrading somewhat at extreme latitudes. As with the sun, a real horizon of hills or buildings will shift what you actually observe.
Frequently asked questions
Why is there no moonrise on some days?
Because moonrise slides about fifty minutes later each day. Eventually a rise that happened at 23:40 becomes 00:30 the following day, and the day in between has none.
How accurate are these times?
Within about fifteen minutes. This uses a simplified lunar model; a full ephemeris would be sharper, and local terrain shifts what you actually see regardless.
Does the moon rise in the east?
Broadly yes, but the exact point moves considerably through the month and with your latitude, much more than the sun's does.
Why is the moon sometimes visible in daylight?
Because its position in the sky is set by its orbit, not by the sun. Away from new moon it is often above the horizon during the day and bright enough to see.
Why does moonrise get later each day?
The moon moves about thirteen degrees along its orbit daily, so the Earth has to turn roughly fifty minutes further for it to appear.
Can the moon be up all day?
Near full moon it is above the horizon mostly at night; near new moon it rises and sets close to the sun and is lost in daylight.
How accurate are the times?
Within a couple of minutes for most locations, with a little more error at extreme latitudes and where the local horizon is not flat.
Can I see a whole month at once?
Yes. A month view is the useful one here, because the fifty-minute daily slip only becomes visible across several days.
Why is moonset sometimes before moonrise in the table?
Because the two events belong to different cycles on that calendar day. Reading down a whole month makes the pattern clear.
Does the moon always show the same face?
Yes. It rotates once per orbit, so the same hemisphere always faces us. The far side is not permanently dark — it receives just as much sunlight, simply on the opposite schedule.
Why do the times differ from an almanac?
Almanacs often quote times for a specific observing site with its own horizon and elevation, and some use a slightly different definition of the moment the disc clears the horizon. A few minutes of disagreement is normal.