- What is a full Moon?
- What are the phases of the Moon?
- How often does a full Moon occur?
- 2025 full Moon calendar
- Is there a full Moon every month?
- Why can't we see the far side of the Moon?
- Can you have a full Moon during the day?
- What is a supermoon?
Want more? Meet real astronomers and learn more about all the moons in our Solar System at the Royal Observatory's Moons Beyond Counting planetarium show.
What is a full Moon?
A full Moon is when the Moon appears as a complete circle in the sky. We see it as a circle because the whole side of the Moon facing the Earth is lit up by the Sun's rays.
The Moon produces no visible light of its own, so we can only see the parts of the Moon that are lit up by other objects.
A small amount of light comes from distant stars and the reflection of light from the Earth (known as 'Earthshine'). However the main source of light for the Moon is the Sun.
What are the phases of the Moon?
The Moon appears as different shapes in the sky depending on its 'phase', from new Moon to full Moon via 'waxing' (growing) and 'waning' (shrinking) moons. These phases are determined by the relative positions of the Sun, Earth and Moon.
If the Moon is between the Earth and the Sun in its orbit, then the back side of the Moon is lit and the side facing the Earth is in darkness. This is called a new Moon.
If the Moon is on the opposite side of the Earth to the Sun, then the near side of the Moon will be fully lit: a full Moon.
How often does a full Moon occur?
A full Moon happens roughly every 29.5 days. This is the length of time it takes for the Moon to go through one whole lunar phase cycle.
Want more space and astronomy?
Join our newsletter to get astronomy guides, space news and the latest updates from the Royal Observatory.
When is the next full Moon?
The next full Moon is on 13 January 2025 at 10.27pm in the UK. This is the first full Moon of the year, sometimes known as the 'Wolf Moon'.
Check the calendar below to see all the full Moon dates in 2025.
Full Moon calendar 2025
| Full Moon date and time | Full Moon name |
|---|---|
| 13 January (10.27pm) | Wolf Moon |
| 12 February (1.53pm) | Snow Moon |
| 14 March (6.55am) | Worm Moon |
| 13 April (1.22am) | Pink Moon |
| 12 May (5.56pm) | Flower Moon |
| 11 June (8.44am) | Strawberry Moon |
| 10 July (9.37pm) | Buck Moon |
| 9 August (8.55am) | Sturgeon Moon |
| 7 September (7.09pm) | Corn/Harvest Moon |
| 7 October (4.48am) | Hunter's Moon |
| 5 November (1.19pm) | Beaver Moon |
| 4 December (11.14pm) | Cold Moon |
All times show the time of the full Moon at the Royal Observatory's home in London, either in GMT or BST depending on the time of year. For full details see the 2025 Guide to the Night Sky.
Is there a full Moon every month?
The Moon’s phases and the months of the year are closely linked - the word 'month' even takes its root from the word 'moon'.
A month was originally defined to be either 29 or 30 days, which is roughly equal to the 29-and-a-half-day lunar cycle. However, extra days were later added to some calendar months, in order to make 12 months add up to 365 days – a complete solar year.
Because our modern calendar isn’t quite in line with the Moon’s phases, it's possible to have more than one full Moon in a month. This is commonly known as a blue moon.
Why can't we see the far side of the Moon?
The Moon is in what astronomers call 'synchronous rotation' with Earth, which means the same side of the Moon always faces us.
As this animation courtesy of NASA's Scientific Visualization Studio shows, the Moon rotates at the same rate as its orbital motion.
We may not be able to see the far side of the Moon from Earth, but it isn't true that there is always one 'dark' side of the Moon. Just like on Earth, all parts of the Moon will receive sunlight at some point during the lunar day.
Photos of the Moon
See some of the standout images from Astronomy Photographer of the Year, an annual competition hosted by Royal Observatory Greenwich.
2 / 11
Shadow Peaks of Sinus Iridum
© Gábor Balázs
3 / 11
Ball of Rock
"This 78% Moon is blended with a previous Full Moon to create a composite giving the effect of a 3D sphere. This is only possible due to extremely favourable libration between the two images. The image is a 22-panel mosaic. Each panel is 400 frames stacked and manually stitched together."
4 / 11
A Rocky Rise
"This is an image of the Full Moon rising over Church Rock in Broadhaven, Pembrokeshire. I stood on the beach at Broadhaven for a couple of hours waiting for the Moon to rise. The clouds initially hid the Moon and as I was walking away it appeared among the clouds, adding a nice effect over it. I took two shots for the image: one for the Moon and one with a faster shutter speed to catch a flock of birds flying around the rock."
5 / 11
Lunar Lander
"Here, the Snow Moon sets over Clifton Suspension Bridge in Bristol. This was a fluke of a morning. I hadn’t actually intended to head out to photograph the Moon and was on my way into town to walk the dog!"
7 / 11
The Moon And the Shard
8 / 11
Moon with Ancient Pagoda
"When I was little, my grandma often told me mythical tales from Chinese folklore, in which deities lived in palaces in heaven. Now that I have grown up, I use photography to depict such scenes from these stories. The Jinyun Pagoda on Jinyun Mountain in Chongqing is a classical ancient Chinese pagoda and one of the stories features a Full Moon juxtaposed with this very pagoda."
9 / 11
HDR Partial Lunar Eclipse With Clouds
10 / 11
Moon Base
"This aptly named image could almost be a model set from a 1950s/1960s science fiction television programme! The surreal atmosphere of this image is greatly enhanced by the high thin cloud and the monochrome palette with the Full Moon adding drama to the scene, either indicating serenity or impending doom (depending on the plot)." - Mandy Bailey, Astronomy Secretary for the Royal Astronomical Society, Open University lecturer and freelance science editor
11 / 11
Arch of Selene (I Saw the Whole of the Moon)
Why is there a full Moon in the daytime?
Some of the times included in the table show full moons happening in the daytime. How can this be?
The time refers to the exact moment when the Sun and Moon are aligned on opposite sides of the Earth. This moment is known as the 'syzygy' of the Sun-Earth-Moon system, and can happen at any time day or night.
The Moon will still look full either on the night before or the evening after the exact moment of 'full Moon'.
What is a supermoon?
The distance between the Moon and the Earth varies, because the Earth is not right at the centre of the Moon’s orbit and the Moon’s orbit is not a circle (it’s an ellipse).
The moment when the Moon is closest to the Earth is called a lunar perigee. When the Moon is furthest away it is known as a lunar apogee.
If the lunar perigee occurs very close to a full Moon, then we see what is sometimes referred to as a supermoon. If a lunar apogee occurs very close to a full Moon then we see a micromoon.
Find more great space and astronomy facts
Learn about the cosmos with Royal Observatory Greenwich.
15 awe-inspiring astronomy discoveries
Discover 15 incredible astronomy facts that might just change how you see the Universe
2025 guide to the night sky
Find out what to see in the night sky in 2025 with the Royal Observatory's astronomy calendar
Night sky highlights
Read our monthly night sky highlights blog from Royal Observatory astronomers to discover what to look out for in the sky
Guide to lunar eclipses
Find out what a lunar eclipse is and when the next total lunar eclipse in the UK will occur
Artemis Programme: what you need to know about NASA’s Moon missions
NASA's Artemis missions aim to land the first woman and person of colour on the Moon, create a lunar base, and lay the groundwork for a future trip to Mars!
How to photograph the Moon
Learn how to get started in astrophotography with our step-by-step guide to photographing the Moon
Astronomy courses at the Royal Observatory
Discover our range of astronomy courses suitable for a range of individuals and experience
Never miss a moon
Main image: Color-Full Moon by Nicolas Lefaudeux, Astronomy Photographer of the Year 2019