What is the moon phase today?

This reading comes from Plenilune, my lunar almanac app for iOS: phase, age and illumination are computed with Jean Meeus's algorithms, in the same words the app uses.

The current cycle

The curve follows the disc's illuminated fraction from one new moon to the next. The dot marks the moment you're reading this page.

The next 7 days

Each day's phase and illuminated fraction, computed at noon local time. For the whole month, see the moon calendar for this month.

The next phases

The exact time of the next four principal phases, to the minute.

Today's moon phase on your iPhone home screen

Plenilune's widgets show this reading as an engraved disc, on the home screen or the lock screen. On the lock screen, another widget gives moonrise and moonset for your location, computed on the iPhone, offline.

How to read tonight's moon

Two readings describe the Moon on any given night. The phase says where the Moon stands in its 29.53-day cycle, from new to full and back. The illuminated fraction says how much of the visible disc is lit, from 0% at new moon to 100% at full. To these, add the direction: a waxing moon grows toward full, a waning moon shrinks toward new.

A quick trick for the northern hemisphere: when the lit side is on the right, the Moon is waxing; on the left, it is waning. In the southern hemisphere the trick is exactly reversed. See our guide on why the Moon looks upside down south of the equator.

Why apps can disagree by a percent or a day

The illuminated fraction changes continuously, up to a percent in a few hours near the quarters, so two apps consulted at different moments can differ without either being wrong. Phase names can also differ by a day around the principal phases: the convention Plenilune follows (and this page with it) names new moon, quarters and full moon only on the calendar day when their exact instant falls, in your time zone.