Why does the Moon sometimes shine by day?

The Moon has no light of its own. What we see as moonlight is reflected light from the Sun. Even though moonlight at times turns night almost into day, the Moon’s reflective power is very poor. Compared with a field of snow, which reflects almost 100 per cent of the light falling upon it, the Moon reflects only 7 per cent about the same amount as dark volcanic rock.

But 7 per cent of sunlight is still impressively bright. Sometimes, when the Moon rises during the day, it is bright enough to outshine a dull patch of surrounding sky. Whenever this happens, the Moon will be visible. Even a thin, crescent Moon will stand out plainly.