Greece
Satellite: Sentinel-2 cloudless 2016 by EOX (CC BY 4.0). Outline and points © OpenStreetMap contributors / Natural Earth. North up.
In numbers
49.0km²
Area
70km
Coastline
593m
Highest point
Eros
1,966
People
26°C
Warmest sea
August
6km
To the mainland
When to go to Ýdra
Best for the beach from June to September.
The sea is warmest in August (26 °C) and coolest in February (15 °C). Comfortable swimming (21 °C or more): from June to October.
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 Saronic Islands of Greece
Ýdra is an island in Greece. It covers 49.0 km², with 70 km of coastline. Its highest point, Eros, rises to 593 m. About 1,966 people live on it. The nearest mainland is 6 km away.
Getting there
- Athens Eleftherios Venizelos International Airport (ATH)nearest airport with scheduled flights · 79 km in a straight lineCar hire at ATH airport (Spata-Artemida)Discover Cars · Affiliate link↗
- FerriesHydra - Ermioni, Hydra - Spetses, Piraeus - Hydra, Hydra - Metochi
- 6 km from the mainlanddistance to the nearest continental coast
- From June to Septemberbest months to go (from 30 years of averages)
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 Ýdra.
- 23beachesKaoumithi, Avlaki, Kamínia and 20 more
- 5viewpoints
- 3lighthousesFáros Zoúrvas
- 1ferry terminalsPort of Hydra
- 1marinasHydra
- 1named peaksEros
- 2castles and fortsFroúrio Mandráki Ýdras
- 2ruins and archaeological sites
- 4waymarked walking routes1 - Western Hydra, Hydra Trail 1A and 2 more
- 29hotels, guesthouses and apartments
- 52restaurants, 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
Ýdra in our other atlases
Everything Coastya, Peakyas, Lakeyas and Cascadyas know about what lies inside Ýdra, each with its own numbers.
7mountainsPeakyas
Highest point
588m
Eros
according to Peakyas
7 mountains
on Peakyas, the mountain atlas
- Eros588m
- Pirgos558m
- Fardi Spithari275m
- Koimomeni84m
- Gerakina
- Tsakoni
- Ombori
The shape of the land.
On average the island stands 186 m above the sea. 58 % of it is below 200 m.
- 15 %0–50 m
- 43 %50–200 m
- 41 %200–500 m
- 1 %500–1,000 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.
10 km
All outlines drawn to the same scale (Natural Earth and OpenStreetMap).
Towns on the island
- Ýdra1,900 people
Month by month
The weather on the island.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Afternoon high (°C) | 14 | 14 | 15 | 17 | 21 | 25 | 28 | 28 | 26 | 22 | 19 | 15 |
| Night low (°C) | 12 | 12 | 13 | 15 | 18 | 22 | 25 | 26 | 23 | 20 | 17 | 13 |
| Sea (°C) | 15 | 15 | 15 | 16 | 19 | 22 | 25 | 26 | 25 | 23 | 20 | 17 |
| Rain (mm) | 86 | 72 | 58 | 32 | 24 | 20 | 11 | 8 | 30 | 54 | 82 | 101 |
| Wet days | 12 | 12 | 10 | 6 | 6 | 3 | 2 | 2 | 5 | 7 | 11 | 13 |
| Sun h/day | 4.3 | 5.1 | 6.9 | 8.6 | 10.2 | 12.1 | 12.6 | 11.6 | 9.1 | 6.7 | 4.9 | 3.7 |
| Wind (km/h) | 24 | 24 | 20 | 18 | 15 | 15 | 17 | 19 | 18 | 21 | 22 | 24 |
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 | +0.5 | +0.2 | ±0.0 | +0.6 | −0.1 | −0.1 | +0.3 | +0.8 | +1.1 | +0.6 | +0.8 |
| 2021 | +1.5 | +1.5 | +1.0 | +0.7 | +1.0 | +0.8 | +1.3 | +1.2 | +0.7 | +0.5 | +0.4 | +0.6 |
| 2022 | +0.8 | +0.6 | +0.2 | +0.3 | +0.5 | +0.3 | −0.2 | +0.3 | +1.1 | +0.3 | +0.4 | +1.0 |
| 2023 | +1.7 | +1.0 | +0.7 | +0.4 | −0.6 | −0.1 | +2.0 | +1.5 | +0.7 | +1.1 | +1.8 | +1.5 |
| 2024 | +1.9 | +0.9 | +1.0 | +1.5 | +0.2 | +1.1 | +0.9 | +2.0 | +1.8 | +1.5 | +1.2 | +1.7 |
| 2025 | +1.2 | +1.2 | +1.0 | +0.4 | +0.1 | +0.4 | +1.4 | +0.6 | +1.1 | +0.8 | +1.4 | +1.7 |
+1 warmer than usual −1 cooler than usual
Photos
Seen by visitors.
Nearby
More islands nearby.
About these numbers
| Names, area, population | Wikidata (Q208319) · 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 | Peakyas — Wikidata · CC0; © OpenStreetMap contributors · ODbL; GeoNames · CC BY 4.0 |
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