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| | Astronomy Essentials | Space on Aug 25, 2014

Longest lunar month of 2014 starts on August 25

The longest lunar month of 2014 starts with the August 25 new moon and ends September 24. All you need to know about the varying lengths of the lunar months, here.

The longest lunar month of the year 2014 begins with the new moon of August 25. It ends with the new moon of September 24, 2014. Follow the links below to learn more:

Longest lunar month of 2014

Shortest lunar month of 2014

Lengths of the lunar months in 2014

Why the difference in the lengths of lunar months?

When are the longest and shortest lunar months of 21st century?

Simulated view of the cycle of the moon's phases from new moon to new moon. This cycle is known as the lunar month. From the years 1760 to 2200, the longest lunar month was 29 days 19 hours and 58 minutes and the shortest 29 days 6 hours and 34 minutes.

Simulated view of the moon’s phases. The period of time from new moon to new moon is known as the lunar month, lunation or synodic month. From the years 1760 to 2200, the longest lunar month spans 29 days 19 hours and 58 minutes (Dec. 9, 1787 to Jan. 8, 1778) while the shortest lasts for 29 days 6 hours and 34 minutes (June 12 to July 12, 1885).

Longest lunar month of 2014. The longest lunar month of 2014 – August 25 through September 24 – lasts for 29 days 16 hours and 1 minute.

That’s 3 hours and 17 minutes longer than the mean lunar month of 29 days 12 hours and 44 minutes.

What is a lunar month? It’s just the duration between successive new moons. It’s also sometimes called a lunation or synodic month. Although the lunar month has a mean period of 29.53059 days (29 days 12 hours and 44 minutes), the actual length varies throughout the year.

One lunar month is the period of time from new moon to new moon. As viewed from the north side of The Earth's and moon's orbital planes, the Earth goes counterclockwise around the sun and the moon goes counterclockwise around Earth. Image credit: Wikipedia

One lunar month is the period of time from new moon to new moon. As viewed from the north side of The Earth’s and moon’s orbital planes, the Earth goes counterclockwise around the sun and the moon goes counterclockwise around Earth. Image via Wikipedia

Shortest lunar month of 2014. The shortest lunar month this year happened in between the new moons of January 30 and March 1. (There was no new moon in February 2014.) This lunar month was only 29 days 10 hours and 21 minutes long, or 2 hours and 23 minutes shorter than the mean lunar month of 29 days 12 hours and 44 minutes.

All added up, that means the year’s longest lunar month in 2014 exceeds the year’s shortest by 5 hours and 40 minutes.

Lengths of the lunar months in 2014


Successive new moons Length of lunar month
January 1 to January 30 29 days 10 hours 24 min
January 30 to March 1 29 days 10 hours 21 minute
March 1 to March 30 29 days 10 hours 45 min
March 30 to April 29 29 days 11 hours 30 min
April 29 to May 28 29 days 12 hours 26 min
May 28 to June27 29 days 13 hours 28 min
June 27 to July 26 29 days 14 hours 33 min
July 26 to August 25 29 days 15 hours 31 min
August 25 to September 24 29 days 16 hours 01 minute
September 24 to October 23 29 days 15 hours 43 min
October 23 to November 22 29 days 14 hours 36 min
November 22 to December 22 29 days 13 hours 04 min

Sources: Astropixels.com and TimeandDate.com

Image credit: NASA. The moon's orbit is closer to being a circle than the diagram suggests. Successive new moons at the vicinity of apogee make for a longer-than-average lunar month. Successive new moons at the vicinity of perigee make for a shorter-than-average lunar month.

Image credit: NASA. The moon’s orbit is closer to being a circle than the diagram suggests. Successive new moons at the vicinity of apogee make for a longer-than-average lunar month. Successive new moons at the vicinity of perigee make for a shorter-than-average lunar month.

Why the difference in the lengths of lunar months? In a nutshell, the longest lunar month of the year occurs when the successive new moons coincide closely with lunar apogee – the moon’s farthest point to Earth in its orbit.

In contrast, the year’s shortest lunar month takes place when the successive new moons fall appreciably close to lunar perigee – the moon’s closest point to Earth in its orbit.

In 2014, the year’s longest and shortest lunar months do not actually showcase great extremes. In fact, the longest and shortest lunar months in the years ahead will vary more greatly from the mean.

The longest lunar months happen when successive new moons occur near lunar apogee – and in addition, the Earth is near perihelion (Earth’s closest point to the sun in its orbit). Because Earth is always closest to the sun in early January, the very longest lunar months take place in between December and January new moons.

On the other hand, extremely short lunar months happen when successive new moons fall near lunar perigee – and in addition, the Earth is near aphelion (Earth’s farthest point from the sun in its orbit). Because Earth is always at aphelion in early July, the very shortest lunar months take place in between June and July new moons.

When are the longest and shortest lunar months of 21st century? The longest lunar month of the 21st century (2001 to 2100) occurs in between the December 2017 and January 2018 new moons. With a length of 29 days 19 hours and 47 minutes, this particular lunar month exceeds the mean by a whopping 7 hours and 3 minutes.

The century’s shortest lunar month takes place in between the new moons of June and July 2053, a period of 29 days 6 hours and 35 minutes. That’s 6 hours and 9 minutes shorter than the mean.

Incidentally, exceptionally long or short lunar months repeat in cycles of 9 years.

Each year, the shortest and longest lunar months come a few months later in the year. For instance, in 2015, the shortest lunar month happens in between the April and May new moons; and the longest one in between the October and November new moons. Click here for a complete listing for the length of each lunar month in the 21st century.

Bottom line: A lunar month is the duration between successive new moons. It’s also sometimes called a lunation or synodic month. Although the lunar month has a mean period of 29.53059 days (29 days 12 hours and 44 minutes), the actual length varies throughout the year. The longest lunar month of the year begins with the new moon of August 25, 2014 and ends with the new moon of September 24, 2014.