Satellite: Sentinel-2 cloudless 2016 by EOX (CC BY 4.0). Outline and points © OpenStreetMap contributors / Natural Earth. North up.
In numbers
8.1km²
Area
28km
Coastline
90m
Highest point
2,167
People
17°C
Warmest sea
September
16km
To the mainland
When to go to Alderney
Good all year round.
The sea is warmest in September (17 °C) and coolest in March (9 °C). The water never reaches 21 °C: bring a wetsuit.
Averages 1991–2020. Sea: NOAA OISST, the water within 35 km of the coast. Air, rain and sun: NASA POWER. Best months weigh warm afternoons (23–30 °C), sea of 24 °C or more and few wet days.
One of the Channel Islands. Part of the Bailiwick of Guernsey, which is one of the British Crown Dependencies.
Alderney is an island in Guernsey. It belongs to Channel Islands. It covers 8.1 km², with 28 km of coastline. Its highest point rises to 90 m. About 2,167 people live on it. The nearest mainland is 16 km away.
Getting there
- Alderney Airport (ACI)airport on the island, with scheduled flightsCar hire at GCI airport (Saint Peter Port)Discover Cars · Affiliate link↗
- FerriesGuernsey - Alderney, Cherbourg-en-Cotentin (F) - Alderney (GBG), Diélette - Alderney
- 16 km from the mainlanddistance to the nearest continental coast
Plan the trip
Ferries, stays and things to do
Some links above are affiliate links: if you book through them we may earn a commission, at no extra cost to you. It never changes what the data on this page says.
On the island
What you find on Alderney.
- 17beachesCorblets Beach, Saye Beach, Platte Saline and 14 more
- 3viewpoints
- 1lighthousesAlderney Lighthouse
- 1marinasBraye Harbour
- 1named peaksAlderney
- 12castles and fortsFort Platte Saline, Roselle Battery, Fort Albert and 9 more
- 1campsitesSaye Beach Campsite
- 11hotels, guesthouses and apartments
- 12restaurants, cafés and bars
Counted in OpenStreetMap, the map anyone can edit, inside the island's outline. A low number may only mean nobody has mapped it yet.
Cross-checked with our atlases
Alderney in our other atlases
Everything Coastya, Peakyas, Lakeyas and Cascadyas know about what lies inside Alderney, each with its own numbers.
1beachCoastya
2mountainsPeakyas
Beach with the warmest sea
16.9°C
Platte Saline
sea in the warmest month · according to Coastya
The shape of the land.
On average the island stands 49 m above the sea. 100 % of it is below 200 m.
- 47 %0–50 m
- 53 %50–200 m
Share of the island's area in each altitude band, from the Copernicus DEM (30 m, read at 30–240 m on large islands).
Size, for real
Next to islands you may know.
5 km
All outlines drawn to the same scale (Natural Earth and OpenStreetMap).
Towns on the island
- St Anneno census figure
Month by month
The weather on the island.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Afternoon high (°C) | 10 | 9 | 10 | 11 | 13 | 15 | 17 | 18 | 17 | 16 | 13 | 11 |
| Night low (°C) | 8 | 8 | 8 | 9 | 11 | 14 | 16 | 16 | 16 | 14 | 12 | 9 |
| Sea (°C) | 10 | 10 | 9 | 10 | 11 | 13 | 15 | 16 | 17 | 16 | 14 | 12 |
| Rain (mm) | 96 | 79 | 68 | 47 | 51 | 46 | 46 | 54 | 47 | 96 | 110 | 106 |
| Wet days | 16 | 14 | 12 | 11 | 10 | 9 | 9 | 10 | 11 | 16 | 18 | 18 |
| Sun h/day | 1.3 | 2.7 | 4.5 | 7.4 | 8.5 | 8.8 | 8.8 | 7.6 | 6.5 | 3.7 | 1.9 | 1.1 |
| Wind (km/h) | 33 | 32 | 28 | 23 | 22 | 20 | 20 | 21 | 24 | 28 | 32 | 33 |
Averages 1991–2020 for the ~55 km NASA POWER cell over the island; the sea from NOAA OISST.
Recent years
Warmer and cooler years at sea.
Each month's sea temperature compared with its 1991–2020 average, in degrees.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020 | +0.5 | +0.7 | +0.4 | +0.4 | +0.4 | +0.7 | +0.8 | +1.0 | +0.7 | +0.1 | +0.1 | +0.3 |
| 2021 | +0.3 | +0.2 | +0.2 | −0.4 | −0.4 | −0.2 | −0.3 | −0.3 | +0.5 | +0.6 | +0.8 | +0.7 |
| 2022 | +0.8 | +0.9 | +1.0 | +0.9 | +1.2 | +0.6 | +1.0 | +0.9 | +1.2 | +0.9 | +0.9 | +0.6 |
| 2023 | +1.0 | +0.5 | +0.4 | +0.3 | +0.6 | +0.5 | +0.8 | +0.4 | +1.0 | +1.0 | +0.5 | +0.7 |
| 2024 | +0.8 | +1.1 | +1.3 | +1.3 | +1.1 | +1.0 | +0.9 | +0.7 | +0.3 | +0.7 | +1.0 | +0.6 |
| 2025 | +0.7 | +0.5 | +0.6 | +1.0 | +1.0 | +1.3 | +1.5 | +1.0 | +0.3 | +0.4 | +0.3 | +0.6 |
+1 warmer than usual −1 cooler than usual
Photos
Seen by visitors.
Nearby
More islands nearby.
Guernsey
Guernsey63 km²110 m40 km away
SarkGuernsey5.3 km²114 m33 km away
HermGuernsey1.3 km²66 m33 km away
Isle of Wight
United Kingdom380 km²241 m127 km away
Isle of PortlandUnited Kingdom12 km²149 m94 km away
Jersey
Jersey120 km²143 m56 km away
La MotteJersey0.01 km²8 m62 km away
Brownsea IslandUnited Kingdom2.1 km²39 m110 km awayAbout these numbers
| Names, area, population | Wikidata (Q179313) · CC0 |
|---|---|
| Outline | © OpenStreetMap contributors · ODbL |
| Sea temperature | NOAA OISST v2.1 · 1991–2020 |
| Climate | NASA POWER · 1991–2020 |
| Relief, 3D model | Copernicus DEM GLO-30 · © DLR e.V., © Airbus Defence and Space GmbH, Copernicus/ESA |
| Beaches, ports, lighthouses, trails | © OpenStreetMap contributors · ODbL |
| Towns | GeoNames · CC BY 4.0 |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
| Beaches, mountains, lakes and waterfalls | Coastya, Peakyas — Wikidata · CC0; © OpenStreetMap contributors · ODbL; GeoNames · CC BY 4.0; NOAA OISST |
Every figure is an average, an estimate or a count from a public dataset. Licences and methods: data sources.
The family
Do you prefer beaches, lakes, mountains, waterfalls, islands, rivers or canyons?
Same idea, other landscapes: field atlases built on open data, month by month, in seven languages.
beaches
Find your beach: sea temperature, sun and swimming month by month.Visit 
lakes
Every lake on Earth: water temperature, ice, depth and the shore.Coming soonVisit mountains
Every summit in 3D: summit weather, the 0 °C line, huts and trails.Visit 
waterfalls
Every waterfall: height, flow month by month and when it roars.Coming soonVisit 
islands
Every island from the sea up: size, sea temperature, ferries and 3D.You are here
rivers
Every river from source to sea: the journey, the flow and the basin in numbers.Visit 
canyons
Every canyon cut to scale: depth to the floor, rim and floor temperatures, trails and viewpoints.Visit