Moon Phase Calendar

What are moon phases?

The Moon orbits Earth roughly every 29.5 days (a synodic month), and its appearance changes as sunlight illuminates different portions of its surface. The four primary phases are:

• New Moon — the Moon is between Earth and the Sun; the side facing Earth is dark.
• First Quarter — the right half of the Moon is illuminated (in the Northern Hemisphere).
• Full Moon — the entire face of the Moon is illuminated by the Sun.
• Last Quarter — the left half of the Moon is illuminated (in the Northern Hemisphere).