The Moon in Helena, Montana, United States

Reading the Moon

The phase tells you how much of the Moon's disc is lit and whether it is waxing (growing) or waning (shrinking). A new moon rises and sets with the Sun and leaves the sky at its darkest — best for deep-sky and meteor watching. A full moon rises around sunset and stays up all night, washing out faint stars but lighting the landscape.

Moonrise and moonset shift by roughly 50 minutes each day, so the Moon keeps different company with the Sun through the month. Use the times above to plan moonlit landscapes, or to know when the sky will be dark.

Data: Meeus astronomical algorithms. How we calculate this