Moonrise and moonset

A full moon setting behind San Gorgonio Mountain, California, on a midsummer morning

Moonrise and moonset are when the Moon climbs above the horizon and sinks below it daily (or nightly – depending on the moon phase). The moon, like all other sky objects, rises in the east and sets in the west^[1] due to the Earth's rotation.^[2]

Direction and time[]

Direction[]

The earth rotates to the east, so all sky objects, including the sun, the moon, and the stars, rise in the east and set in the west.^[2] If an object is not visible because it is below the horizon, then eventually it will be visible in the east after rising, not in the west. Seasonal variation means that sometimes they rise in the east-northeast or east-southeast, and sometimes they set in the west-southwest or west-northwest.^[1]

Time[]

A waxing gibbous moon, rising over mountains with coniferous trees

The moon's position relative to the earth and the sun determines the moonrise and moonset time. For example, a last quarter rises at midnight and sets at noon.^[3] A waning gibbous is best seen from late night to early morning.^[4] The moon rises 30 to 70 minutes later each day/night than the day/night before, due to the fact that the moon moves 13 degrees every day. Hence, the earth must move 13 degrees after completing one rotation for the moon to be visible.^[5]

Moonrise/moonset for different moon phases

Lunar phase (illustration as seen from northern hemisphere)	Moonrise[a]	Culmination time (highest point)	Moonset	Best seen
New moon	Sunrise	Noon	Sunset	Not visible unless there is an eclipse
Waxing crescent	Late morning	Afternoon	Late evening	Afternoon to early evening
First quarter	Noon	Sunset	Midnight	Early evening to late night
Waxing gibbous	Afternoon	Late evening	Predawn	Early evening[6] and most of night
Full moon	Sunset	Midnight	Sunrise	Sunset to sunrise (all night)
Waning gibbous	Late evening	Predawn	Late morning	Most of night and early morning[4]
Last quarter	Midnight[3]	Sunrise	Noon[3]	Predawn to post-sunrise
Waning crescent	Predawn	Late morning	Afternoon	Predawn to afternoon

What the moon looks like during moonrise/moonset[]

Moon illusion[]

The moon appears to be larger at moonrise or moonset due to an illusion. This illusion, known as the moon illusion, is caused by an effect of the brain. There is no certain explanation for the moon illusion yet. However, it's most likely because of how the brain perceives object at different distances, and/or the distance we expect objects to be from us when they are near the horizon.^[7]

Color[]

The moon appears to be more yellowish near the horizon. This is for the same reason the sun and/or sky appears to be orangey-red at sunrise/sunset. When the moon is near the horizon, the light coming from it has to pass through more layers of atmosphere. This scatters the blue away, and leaves yellow, orange, and red.^[8] This is also the reason the moon appears red during a deep partial or total lunar eclipse.^[9]

Notes[]

References[]