First Quarter Moon

First Quarter Moon Phase


What is a first quarter moon? The first quarter moon, sometimes known as a half moon, is defined to occur when the excess of the apparent ecliptic (celestial) longitude of the Moon over that of the Sun is 90 degrees. This means that one-half of the Moon appears to be illuminated by direct sunlight and the fraction of the Moon’s disk that is illuminated is increasing. Each new lunar cycle is measured beginning at each new moon and the first quarter moon occurs when the Moon is one-quarter of the way around the sky (i.e., along its orbit) from new moon.

First Quarter Moon Dates / Next First Quarter Moon

When is the next first quarter moon? A first quarter moon comes a week after new moon. The average calendrical month, which is 1/12 of a year, is about 30.44 days, while the Moon’s phase (synodic) cycle repeats on average every 29.53 days. Therefore the timing of the Moon’s phases shifts by an average of almost one day for each successive month. To find out the first quarter moon dates, please see the first quarter moon calendar below.

First Quarter Moon and The Moon Phases

First Quarter Moon

First Quarter Moon

The first quarter moon (often called a “half moon”), happens when the moon is at a 90 degree angle with respect to the Earth and Sun. So we are seeing exactly half of the moon illuminated and half in shadow.

Each lunar cycle begins with a new moon. As the Moon moves eastward away from the Sun in the sky, we see a bit more of the sunlit side of the Moon each night. We call this waxing. After the new moon, the sunlit portion is increasing, but less than half illuminated, so it is a waxing crescent moon. When half of the Moon’s disc is illuminated, we call it the first quarter moon. As the sunlit portion continues to increase, now more than half illuminated, it becomes waxing gibbous moon. When the Moon reaches maximum illumination, a full moon, the Moon has completed one half of the lunar month.

During the second half of the lunar month, the Moon grows thinner each night. We call this waning. The waning gibbous moon phase occurs first, followed by the last quarter moon when half of the Moon’s disc is illuminated. Next is the waning crescent moon, which wanes until the illumination is completely gone; a new moon.

First Quarter Moon Calendar 2012

The first quarter moon calendar for 2012 is expressed in Coordinated Universal Time (UT), the international basis for other time zones. A first quarter moon rises at noon and is high overhead at sunset. It sets around midnight. Astronomers call one lunar cycle a lunation. For first quarter moon times in your city, please use the Time Zone Converter.

Lunation New Moon First Quarter Full Moon Last Quarter
1001   Jan 1 06:15 Jan 9 07:30 Jan 16 09:08
1002 Jan 23 7:39 Jan 31 04:10 Feb 7 21:54 Feb 14 17:04
1003 Feb 21 22:35 Mar 1 01:22 Mar 8 09:40 Mar 15 01:25
1004 Mar 22 14:37 Mar 30 19:41 Apr 6 19:19 Apr 13 10:50
1005 Apr 21 07:18 Apr 29 09:58 May 6 03:35 May 12 21:47
1006 May 20 23:47 May 28 20:16 Jun 4 11:12 Jun 11 10:41
1007 Jun 19 15:02 Jun 27 03:30 Jul 3 18:52 Jul 11 01:48
1008 Jul 19 04:24 Jul 26 08:56 Aug 2 03:27 Aug 9 18:55
1009 Aug 17 15:54 Aug 24 13:54 Aug 31 13:58 Sep 8 13:15
1010 Sep 16 02:11 Sep 22 19:41 Sep 30 03:19 Oct 8 07:33
1011 Oct 15 12:02 Oct 22 03:32 Oct 29 19:50 Nov 7 00:36
1012 Nov 13 22:08 Nov 20 14:31 Nov 28 14:46 Dec 6 15:32
1013 Dec 13 08:42 Dec 20 05:19 Dec 28 10:21  

Moon Phases, Full Moons and Moon Calendars

As the Moon orbits Earth, it changes phase in an orderly way. Follow these links to understand the various phases of the moon.

Full Moons

Full Moon | Full Moon Names | Blue Moon | Wolf Moon | Snow Moon | Worm Moon | Pink Moon | Flower Moon | Strawberry Moon | Buck Moon | Sturgeon Moon | Harvest Moon | Hunters Moon | Beaver Moon | Cold Moon |

Moon Phases

Understanding Moon Phases | New Moon | Waxing Crescent Moon | First Quarter Moon | Waxing Gibbous Moon | Full Moon | Waning Gibbous Moon | Last Quarter Moon | Waning Crescent Moon |

Moon Calendars

Full Moon Calendar | Lunar Calendar | Lunar Eclipse Calendar | Solar Eclipse Calendar | Full Moon Calendar 2011 | Full Moon Calendar 2012 | Full Moon Calendar 2013 | Full Moon Calendar 2014 | Full Moon Calendar 2015 | Full Moon Calendar 2016 | Full Moon Calendar 2017 | Full Moon Calendar 2018 | Full Moon Calendar 2019 | Full Moon Calendar 2020 |

Eclipses & Moon Facts

Lunar Eclipse | Solar Eclipse | Solar Eclipse vs. Lunar Eclipse | Facts About The Moon |