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FullMoon
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FullMoon

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gives the date of the next full moon.

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FullMoon[date]

gives the date of the first full moon after the given date.

Details and Options

  • The instant of full moon is defined by the opposition of the Moon and the Sun in ecliptic longitude.
  • In FullMoon[date], date can be any DateObject expression.
  • Options of FullMoon include:
  • CalendarType Automaticcalendar used to return dates
    DateFormat Automaticformat used to display output dates
    DateGranularity Automaticcalendar granularity of output dates
    Method "EclipticLongitude"method to define moon phases
    TimeDirection 1whether to return the next or last full moon
    TimeSystem Automatictime system of output dates
    TimeZone $TimeZonetime zone of output dates
  • Possible settings for the Method option include:
  • "Illumination"phase defined by fraction of illumination of the Moon
    "EclipticLongitude"phase defined by Moon‐Sun ecliptic longitude difference

Examples

open allclose all

Basic Examples  (2)Summary of the most common use cases

Find the date of the next full moon:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-mu80w2
Out[1]=1

Find the date of the first full moon of the year 2000:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-d01hvb
Out[1]=1

Scope  (3)Survey of the scope of standard use cases

Find the next full moon:

In[1]:=1
✖
https://wolfram.com/xid/0i1l73bvq-xf97h9
Out[1]=1

Find the next full moon after a given date:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-8mnj6x
Out[1]=1

Find full moons very far in the past:

In[1]:=1
✖
https://wolfram.com/xid/0i1l73bvq-w5i14z
Out[1]=1

Find full moons very far in the future:

In[2]:=2
✖
https://wolfram.com/xid/0i1l73bvq-dfoxk7
Out[2]=2

Options  (7)Common values & functionality for each option

CalendarType  (1)

FullMoon returns dates in the Gregorian calendar by default:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-3mrrrz
Out[1]=1

Return dates in the Jewish calendar:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-3d1k0
Out[2]=2

DateFormat  (1)

FullMoon returns dates in a long format by default:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-ittmm5
Out[1]=1

Specify your own format:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-cl1rb4
Out[2]=2

DateGranularity  (1)

FullMoon returns dates with granularity "Instant" by default:

In[1]:=1
✖
https://wolfram.com/xid/0i1l73bvq-jn9w3g
Out[1]=1

Return dates with "Day" granularity:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-xs3gvt
Out[2]=2

Method  (1)

FullMoon uses differences of ecliptic longitudes between the Sun and the Moon by default:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-mvp0g9
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-ixw3o7
Out[2]=2

Use the minimum value of illumination to define the instant of new moon instead:

In[3]:=3
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https://wolfram.com/xid/0i1l73bvq-zgln89
Out[3]=3

TimeDirection  (1)

FullMoon finds the next full moon by default:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-urs1zm
Out[1]=1

Find the previous full moon:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-16q8ju
Out[2]=2

TimeSystem  (1)

FullMoon returns dates in universal time by default:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-xnwyai
Out[1]=1

Return dates in "TT" time instead:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-3okaf3
Out[2]=2

TimeZone  (1)

FullMoon returns dates in your local time zone by default:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-38i25c
Out[1]=1

Return dates in the GMT time zone:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-79xuz0
Out[2]=2

Applications  (1)Sample problems that can be solved with this function

A full moon occurring near perigee, i.e. when the Moon is closest to Earth, is known as a supermoon.

Define a function computing the distance from the Earth to the Moon in kilometers:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-on4exe

Find all the full moons between years 2023 and 2026:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-hsf2xb

Plot distances during that period and mark the full moons as purple points:

In[3]:=3
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https://wolfram.com/xid/0i1l73bvq-mkiom0
Out[3]=3

The full moons occurring at smaller distances from Earth, say under 360,000 km, are the supermoons:

In[4]:=4
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https://wolfram.com/xid/0i1l73bvq-cotbin
Out[4]=4

Properties & Relations  (7)Properties of the function, and connections to other functions

At the instant of full moon, the Moon and the Sun have opposite ecliptic longitudes:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-w5u834
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-66xejg
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0i1l73bvq-74p13s
Out[3]=3

Find the next 20 full moons:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-eag07l
Out[1]=1

The distance between full moons varies between 29.26 and 29.80 days:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-xmsq2d
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0i1l73bvq-j2uxp
Out[3]=3

The average synodic month is about 29.53 days:

In[4]:=4
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https://wolfram.com/xid/0i1l73bvq-6wj7cq
Out[4]=4
In[5]:=5
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https://wolfram.com/xid/0i1l73bvq-02yvs4
Out[5]=5

FullMoon returns the date of the next full moon:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-5oguyw
Out[1]=1

Use NewMoon to find the date of the next new moon, which may be before or after that full moon:

In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-c9xmae
Out[2]=2

Use MoonPhaseDate to find the date of any phase of the Moon:

In[3]:=3
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https://wolfram.com/xid/0i1l73bvq-jvlwgj
Out[3]=3

MoonPhase computes the phase fraction of illumination, which is close to 1 for a full moon:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-wf5niy
In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-q6ah3j
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0i1l73bvq-sown73
Out[3]=3

The maximum of illumination is given by this alternative method of computation:

In[4]:=4
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https://wolfram.com/xid/0i1l73bvq-o6xt8r
Out[4]=4
In[5]:=5
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https://wolfram.com/xid/0i1l73bvq-r126dx
Out[5]=5

This curve represents fraction of illumination for an hour around the maximum, with fullmoon in red:

In[6]:=6
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https://wolfram.com/xid/0i1l73bvq-dxeqjw
Out[6]=6

Full moons correspond to semi-integer lunation numbers:

In[1]:=1
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https://wolfram.com/xid/0i1l73bvq-1la6ei
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0i1l73bvq-zjjwnc
Out[2]=2

Therefore, an alternative way of finding full moons is calling FromLunationNumber with semi-integers:

In[3]:=3
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https://wolfram.com/xid/0i1l73bvq-zm94x
Out[3]=3

Full moons are oppositions of the Moon with respect to the Sun, as observed from the center of the Earth:

In[1]:=1
✖
https://wolfram.com/xid/0i1l73bvq-5ypkeb
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0i1l73bvq-0u4gyu
Out[2]=2

Every lunar eclipse happens within a few minutes of a full moon:

In[1]:=1
✖
https://wolfram.com/xid/0i1l73bvq-bjiiyn
Out[1]=1
In[2]:=2
✖
https://wolfram.com/xid/0i1l73bvq-flc4i0
Out[2]=2

Only some of the 12 or 13 full moons in a year are close to lunar eclipses:

In[3]:=3
✖
https://wolfram.com/xid/0i1l73bvq-oty51l
Out[3]=3
Wolfram Research (2024), FullMoon, Wolfram Language function, https://reference.wolfram.com/language/ref/FullMoon.html (updated 2025).
✖
Wolfram Research (2024), FullMoon, Wolfram Language function, https://reference.wolfram.com/language/ref/FullMoon.html (updated 2025).

Text

Wolfram Research (2024), FullMoon, Wolfram Language function, https://reference.wolfram.com/language/ref/FullMoon.html (updated 2025).

✖
Wolfram Research (2024), FullMoon, Wolfram Language function, https://reference.wolfram.com/language/ref/FullMoon.html (updated 2025).

CMS

Wolfram Language. 2024. "FullMoon." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2025. https://reference.wolfram.com/language/ref/FullMoon.html.

✖
Wolfram Language. 2024. "FullMoon." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2025. https://reference.wolfram.com/language/ref/FullMoon.html.

APA

Wolfram Language. (2024). FullMoon. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/FullMoon.html

✖
Wolfram Language. (2024). FullMoon. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/FullMoon.html

BibTeX

@misc{reference.wolfram_2025_fullmoon, author="Wolfram Research", title="{FullMoon}", year="2025", howpublished="\url{https://reference.wolfram.com/language/ref/FullMoon.html}", note=[Accessed: 29-March-2025 ]}

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@misc{reference.wolfram_2025_fullmoon, author="Wolfram Research", title="{FullMoon}", year="2025", howpublished="\url{https://reference.wolfram.com/language/ref/FullMoon.html}", note=[Accessed: 29-March-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_fullmoon, organization={Wolfram Research}, title={FullMoon}, year={2025}, url={https://reference.wolfram.com/language/ref/FullMoon.html}, note=[Accessed: 29-March-2025 ]}

✖
@online{reference.wolfram_2025_fullmoon, organization={Wolfram Research}, title={FullMoon}, year={2025}, url={https://reference.wolfram.com/language/ref/FullMoon.html}, note=[Accessed: 29-March-2025 ]}