Guides
When is the next new moon?
The date and hour below are computed the moment you open this page, with the same astronomical algorithms as the Plenilune app, in your own time zone.
What a new moon is
The new moon is the instant when the Moon passes between the Earth and the Sun, lined up with the Sun as seen from Earth. Its daylit half faces entirely away from us, and it stands in the daytime sky beside the Sun. So there is nothing to see: the new moon is the one phase that is defined by its invisibility. The lunar month, from one new moon to the next, lasts 29.53 days on average.
The Moon does not pass exactly in front of the Sun each month, because its orbit is tilted by about five degrees. When it does, there is a solar eclipse: two to five times a year, somewhere on Earth, and only ever at new moon.
The first crescent
One or two evenings after the instant, a thin arc appears low in the west just after sunset, and sets soon after: the young Moon. Spotting it under 24 hours old is a sport among observers, and a matter of consequence in the calendars that begin their months with the sighting of the crescent rather than with the computed instant. The month of Ramadan, and every month of the Islamic calendar, starts that way; so, traditionally, did the Hebrew month. The Chinese calendar takes the astronomical new moon itself as the first day of the month, which is why Chinese New Year always falls on the day of a new moon.
What the new moon is good for
- The darkest skies of the month: the week around new moon is when the Milky Way, meteor showers and faint objects are best seen.
- The lowest and highest tides: at new moon, as at full moon, the Sun and Moon pull along the same line, and the tidal range is greatest. These are the spring tides, in any season.
- The traditional start of the gardener's month: the old calendars keep the waxing Moon, which begins here, for sowing what grows above ground. Tradition, not measured effect.
Questions
- Can you see the new moon?
- No. At the instant of new moon the lit side faces away from Earth and the Moon stands next to the Sun in the daytime sky. The first thing visible is the young crescent, one or two evenings later, low in the west after sunset.
- How long is it from new moon to full moon?
- About 14.8 days, half of the 29.53-day synodic month. The exact interval varies by several hours from one month to the next, because the Moon's speed along its orbit is not constant.
- Why is the new moon not an eclipse every month?
- Because the Moon's orbit is tilted about five degrees to the Earth's. Most months it passes above or below the Sun. Only when new moon falls near one of the two crossing points, the nodes, does the Moon cover the Sun.
- Is the new moon the same time everywhere?
- The instant is the same for the whole planet; only the clock time and, near midnight, the calendar date differ by time zone. This page shows the time in yours.