What Day Is New Moon. The new moon is the first lunar phase of the moon, in opposition to the full moon, which is the last phase. The moon can be seen in the daylit sky at any phase except for the new moon, when it’s invisible to us, and full moon, when it’s below the horizon during the day.

The new moon marks the beginning of a lunar cycle. This means that there’s a new moon about once a month because the moon takes about a month (29.5 days) to orbit earth.