Satellite: Sentinel-2 cloudless 2016 by EOX (CC BY 4.0). Outline and points © OpenStreetMap contributors / Natural Earth. North up.
In numbers
6.4km²
Area
23km
Coastline
51m
Highest point
Coastguard's Look Out Tower
1,723
People
17°C
Warmest sea
August
186km
To the mainland
When to go to St Mary's
Good all year round.
The sea is warmest in August (17 °C) and coolest in March (10 °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.
UK island of the Isles of Scilly
St Mary's is an island in United Kingdom. It belongs to Isles of Scilly. It covers 6.4 km², with 23 km of coastline. Its highest point, Coastguard's Look Out Tower, rises to 51 m. About 1,723 people live on it. The nearest mainland is 186 km away.
Getting there
- Cornwall Airport Newquay (NQY)nearest airport with scheduled flights · 109 km in a straight lineCar hire at NQY airport (Newquay)Discover Cars · Affiliate link↗
- FerriesSt Mary's - Tresco (high tide), St Mary's - Tresco (low tide), St Mary's - St Martin's (high tide), St Mary's - Bryher (low tide)
- 186 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 St Mary's.
- 22beachesToll's Porth, Porthcressa Beach, Porth Minick and 19 more
- 4viewpointsPulpit Rock and 3 more
- 1lighthousesPeninnis Head Lighthouse
- 2ferry terminalsSt Mary's Harbour
- 1marinasSt Mary's Harbour
- 8named peaksBuzza Hill, Carn Thomas, Helvear Hill and 5 more
- 5castles and fortsMorning Point Battery, Woolpack Battery, King Charles' Battery and 2 more
- 15ruins and archaeological sitesHalangy Down Ancient Village, Bant's Carn, Porth Hellick Down Burial Chamber and 12 more
- 2campsitesPelistry Campsite
- 23hotels, guesthouses and apartments
- 17restaurants, 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
St Mary's in our other atlases
Everything Coastya, Peakyas, Lakeyas and Cascadyas know about what lies inside St Mary's, each with its own numbers.
2beaches and covesCoastya
Beach with the warmest sea
17.0°C
Pelistry Bay
sea in the warmest month · according to Coastya
The shape of the land.
On average the island stands 23 m above the sea. 100 % of it is below 200 m.
- 100 %0–50 m
- <1 %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
- Isles of Scilly2,224 people
- St Mary's1,666 people
- Hugh Town1,068 people
Month by month
The weather on the island.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Afternoon high (°C) | 10 | 10 | 10 | 11 | 12 | 15 | 17 | 17 | 16 | 15 | 13 | 11 |
| Night low (°C) | 9 | 8 | 8 | 10 | 12 | 14 | 16 | 16 | 15 | 14 | 11 | 10 |
| Sea (°C) | 11 | 10 | 10 | 10 | 12 | 14 | 16 | 17 | 16 | 14 | 13 | 12 |
| Rain (mm) | 107 | 87 | 81 | 64 | 63 | 63 | 77 | 70 | 64 | 105 | 112 | 113 |
| Wet days | 18 | 15 | 15 | 14 | 13 | 13 | 14 | 15 | 14 | 18 | 20 | 19 |
| Sun h/day | 1.5 | 2.9 | 4.4 | 7.3 | 8.3 | 8.8 | 7.7 | 7.0 | 5.8 | 3.6 | 2.2 | 1.2 |
| Wind (km/h) | 34 | 33 | 30 | 25 | 24 | 22 | 22 | 24 | 25 | 28 | 32 | 34 |
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 | +0.1 | +0.2 | +0.1 | +0.5 | +0.5 | +0.4 | −0.1 | +0.4 | +0.4 | −0.3 | −0.1 | ±0.0 |
| 2021 | −0.1 | +0.1 | +0.5 | +0.1 | −0.5 | +0.6 | +0.9 | ±0.0 | +1.4 | +0.8 | +0.5 | +0.3 |
| 2022 | +0.4 | +0.6 | +0.8 | +0.9 | +1.6 | +0.8 | +0.8 | +1.5 | +1.5 | +0.7 | +0.8 | +0.7 |
| 2023 | +0.9 | +0.5 | +0.8 | +0.4 | +1.1 | +1.5 | +0.3 | −0.2 | +1.4 | +1.1 | +0.4 | +0.5 |
| 2024 | +0.3 | +0.7 | +1.3 | +1.2 | +1.7 | +0.4 | −0.1 | +0.5 | ±0.0 | +0.5 | +0.9 | +0.6 |
| 2025 | +0.7 | +0.8 | +1.2 | +1.5 | +2.4 | +1.5 | +1.3 | +1.2 | −0.2 | +0.1 | +0.4 | +0.5 |
+1 warmer than usual −1 cooler than usual
Photos
Seen by visitors.
Nearby
More islands nearby.
St Michael's Mount
United Kingdom0.09 km²61 m62 km away
LundyUnited Kingdom4.2 km²141 m182 km away
Molène
France0.76 km²25 m195 km away
Île de BatzFrance3.1 km²14 m210 km away
Guernsey
Guernsey63 km²110 m272 km awayBarry IslandUnited Kingdom41 m269 km away
SarkGuernsey5.3 km²114 m288 km away
AlderneyGuernsey8.1 km²90 m295 km awayAbout these numbers
| Names, area, population | Wikidata (Q1329355) · 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 — 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.Coming soonVisit