Why is the Moon visible during the day?
Short answer
We can see the Moon during the day because it reflects sunlight, and enough of that light reaches our eyes even against a bright sky. The Moon is not only in the sky at night. Depending on where it is in its orbit, it can be above the horizon during the day.
Why can we see it in a bright sky?
In daytime, sunlight spreads in many directions as it passes through the air around Earth. This makes the whole sky bright. Stars are still in the sky, but their faint light is lost against that bright background.
The Moon is much closer to Earth than the stars and looks large in the sky. Its sunlit surface reflects enough light for us to pick it out during the day. It often looks pale and is harder to see through clouds or haze.
When we can see the Moon changes with its phase
As the Moon moves around Earth, its position relative to the Sun changes. This changes the phase—the amount of its sunlit half that we can see—and the times it rises and sets. The same positions explain why the Moon appears to change shape.
At first quarter, when the Moon looks about half lit as it grows from the nearly invisible new Moon toward full, it usually rises around midday and sets around midnight. At third quarter, when it looks half lit as it moves from full back toward new, it usually rises around midnight and sets around midday. A full Moon is opposite the Sun: it rises around sunset and sets around sunrise. These times are rough guides and vary with the date and your location.
Why can’t we usually see a new Moon?
Around new Moon, the side facing Earth is mostly unlit. The Moon is also close to the Sun in the sky, so it is usually lost in the bright daylight. The Moon can be above the horizon without being easy to see.