# What percentage of the time can we see the moon during the day?

From sun rise to sun set what percentage of the time is the moon visible?

I saw one thing at the top of google saying an average of 6 hours a day but that seems like a weird way to answer it. Would that be 25% of the it’s visible

Any math or diagrams are much appreciated to better help me grasp it.

• Sounds about right. On average, for any spot on the Earth's surface, the Sun is above the horizon 1/2 of the time. On average, the Moon is above the horizon 1/2 of the time. Both above the horizon: 1/2 x 1/2 =1/4 = 25%. Sep 14, 2021 at 23:29
• @notovny yeah I figured it would be 25% but saying an average of six hours a day just seemed like a really bad way to get that across Sep 14, 2021 at 23:39
• How do you define "see the moon during the day?" Any time it's not a 100% true new moon (solar eclipse), you can technically see the moon if you know exactly where to look and have an optical aid, if it's up. Meaning that it would be just about 50% that it's visible in the sky. Multiply that with 50% of the time the sun's visible, and you get 25%. I also assume you mean "when the sun is above the horizon" by "day?" This assumes a spherical Earth, spherical moon, Moon orbits the equator, and is on a circle orbit. It's slightly more complicated than that, which would alter the numbers a bit. Sep 14, 2021 at 23:54
• Sep 15, 2021 at 3:17
• I'd reduce that by a couple of percent. It's really hard to see the Moon a day or so either side of New Moon. Sep 15, 2021 at 4:56

As is apparent, on the day of first quarter, sun and moon are at 90$$^\circ$$ to each other. Imagine it is noon, you are directly facing the sun. If you look to one side, you see the half moon just rising above the eastern horizon. Now imagine it is sunset. The sun would just be sinking on the western horizon. You would directly face the first quarter moon. So the sun and moon had a common time from noon till sunset, roughly six hours. This common time changes based on the relative positions of sun and moon i.e. the phase of moon.