Surprised to See the Moon During Daylight? Here's the Simple Explanation

First, let’s go over some basic moon facts that factor into this. The moon at an average of 238,855 miles (384,399km) away from us orbits us about every 30 days today and is tidally locked to us meaning it takes exactly the same amount of time to rotate on its axis as it does to orbit around the Earth.

The moon has a day and a night side, determined by which half of it is facing toward the Sun. In fact, moonlight is reflected light from the Sun as opposed to light generated by the moon. As we orbit the Sun and the moon orbits us, we see the Moon go through 8 phases in which parts of the Moon’s face are illuminated by the Sun.

Very simply, since the moon reflects light from the Sun and is extremely close to Earth, it is brighter than either the daytime or nighttime sky. So, when things line up, we see the face of the moon from light reflected from the Sun.

But the moon isn’t always visible in the day. Why isn’t it? Why can we sometimes see it during the day?

It comes down to two main factors: Earth’s atmosphere and the Moon’s orbital cycle.

But let’s dive in further

The Atmosphere and Daylight

If the Earth didn’t have an atmosphere, the moon would be visible from Earth all the time. However, Earth does have an atmosphere, which slightly complicates this relationship.

Gas particles scatter light in short wavelengths such as blue and violet light, causing both absorption and re-emission of light in different directions, giving Earth the blue sky we all know.

For the moon to be seen during the daytime, the moon has to overcome the scattered light from the Sun. Its relative closeness to us means that light reflected from the lunar surface often appears brighter to us than astronomical objects that emit or reflect light further away (i.e. stars and planets).

This visibility can be compromised due to other atmospheric factors. For instance, weather can obviously impact whether or not you can see the moon during the day as clouds and dark skies can obscure it. In addition, air pollution can cause more scattering of light which can impact your ability to see the moon during the daytime.

However, the visibility of the moon during the day is influenced by a number of other factors including the current moon phase and the season.

The Phase of the Moon

The moon is visible during the day for an average of 25 days a month throughout the year. Those missing five days occur around the new moon phase and full moon. Near the new moon, it is too close to the Sun to be seen. Just as we can’t see it during the night during this phase, we can’t see it during the day.

Near the full moon phase, our closest celestial neighbor is only visible at night because it rises at sunset and sets at sunrise.

So near the new moon phase, it’s up in the sky, but we can’t see it due to its location between us and the Sun, meaning the sun’s light overpowers it. Near the full moon phase, it’s not up in the sky during the day time.

Season

The moon is above the horizon for 12 hours a day, but this doesn’t always coincide with daylight hours. For instance, during the winter, days are shorter at mid-latitudes so there is less time for the moon to be visible during the day.

When’s the best time to see the moon during the day?

During the first quarter (one week after the new moon) the moon rises in the afternoon in the eastern sky and third quarter (one week after the full moon) the moon sets in the morning in the western sky.

During both the first quarter and third quarter phases, you have the highest chance of spying the moon during the day despite the other factors listed in this article as they are the longest periods when the moon is visible with the sun in the sky, an average of five to six hours a day.

How can I keep track of the moon’s phases and visibility?

There are many websites that chart the lunar calendar, showing when the moon rises and sets, including Time and Date, The Sky Live, NASA Moon Phases Calendar and Calculator, and ours. Google Calendar and others also offer the Phases of the Moon calendar which you can opt into like other calendars such as national holidays.

You can also simply observe the phases yourself with a moon observation journal to keep up to date on what phase the moon is currently in.

International Observe the Moon Night is upon us (as of this publication) on October 21st, 2023 so check to see if there is an event nearby to join with others. Many of these organizations have other moon and astronomical events throughout the year, but this night, everyone will be looking at the moon.

Conclusion

Our closest celestial neighbor, the moon, is our near-constant companion at night, but also sometimes during the day. Since it is so close to us, its reflected light from the sun makes it the second brightest object in our sky after the sun.

Its phase, the state of our atmosphere, and the season all determine whether or not we can see the moon during the daytime, but the first and third quarter phases are the best times to view the moon during the daytime.

Observing our moon on a regular basis is a wonderful way to track our path through time and space as well as engage in the study of the universe. For more fascinating articles on our moon, check out our Lunar Chronicles.