France Pline · CC BY-SA 3.0
The descent
The entrance, at 150 m.
The real relief above Fosse Dionne, measured on the Copernicus model every 30 m, and the cave going down at the same vertical scale.
The depth is the one published by those who explored it; the shape of the galleries is a sketch, not a survey. No depth has been published for this cave yet.
150m
Entrance altitude
from the 30 m relief model
11°C
Inside, all year
the yearly average outside, at the entrance
140m
Rock above
the highest point within 1.5 km
Inside and outside
11 °C inside, all year.
Deep inside, a cave keeps the average temperature of the year outside: about 11 °C here, in January and in August. In July the afternoon reaches 26 °C at the entrance, 15 °C warmer than inside: take a jacket.
- 5°0°Jan
- 7°0°Feb
- 11°2°Mar
- 16°5°Apr
- 19°9°May
- 23°13°Jun
- 26°15°Jul
- 26°14°Aug
- 22°10°Sep
- 16°7°Oct
- 10°3°Nov
- 6°0°Dec
Outside: afternoon and night averages for 1991–2020 (NASA POWER) brought to the altitude of the entrance. Inside: the yearly average, which deep parts of a cave keep. Near the entrance it follows the weather a little.
Karst spring in France
Fosse Dionne is a cave in France. The entrance is at 150 m.
Getting there.
- Wild cave: only with caving equipmentNo paths or lights inside. Go only with a caving club or a qualified guide.
- Tonnerrenearest town · 0.2 km in a straight line
- Viewpointsnearest viewpoint · 1.5 km from the entrance
- Chalons Vatry airport (XCR)nearest airport with scheduled flights · 103 km in a straight lineCar hire in TroyesDiscover Cars · sponsored link↗
Plan the visit
Guided tours, a bed nearby, a car.
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.
From above.
The ground above the cave, with the relief shaded, the line of the section and what people have mapped around the entrance.
N
1.5 km
Sentinel-2 cloudless 2016 (EOX, CC BY 4.0), 6.0 × 6.0 km, north up. The line is the section above. Points © OpenStreetMap contributors.
Around the entrance.
- 1viewpoints within 3 km
- 5marked hiking routes within 3 kmLes Vignes de l'Empereur, Les coteaux d'Epineuil, Forêt de Tonnerre and 2 more
- 40car parks within 2 km
- 10information boards and visitor centres within 3 km
- 7bus stops within 2 km
- 2campsites within 8 kmCamping La Cascade, Aire de Epineuil
- 24hotels and guesthouses within 8 kmHôtel du Centre, Saint-Nicolas, Auberge de Bourgogne and 21 more
- 15restaurants and cafés within 3 km
- other cave entrances within 3 km
- springs within 2 km
- sinkholes within 3 km
- caving clubs and spots within 15 km
- climbing crags within 3 km
- named waterfalls within 4 km
Counted in OpenStreetMap, the map anyone can edit, around the entrance. A low number may just mean nobody has mapped it yet. © OpenStreetMap contributors (ODbL).
Towns nearby
- Tonnerre0.2 km in a straight line
- Tanlay8.6 km in a straight line
- Flogny-la-Chapelle13 km in a straight line
- Chablis14 km in a straight line
- Ligny-le-Châtel17 km in a straight line
- Ancy-le-Franc17 km in a straight line
- Ervy-le-Châtel21 km in a straight line
- Vergigny23 km in a straight line
In our other atlases
What else is around Fosse Dionne.
The river at the entrance, the waterfalls, the lakes, the mountains and volcanoes above, the canyons, beaches and islands nearby — from our other atlases.
Riveryas1 rivers at the entranceFigures from the sister sites' databases (Wikidata, HydroATLAS, GeoNames, NOAA, OpenStreetMap). Links open when each site is online.
Month by month
The weather outside, at the entrance.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Afternoon | 5 | 7 | 11 | 16 | 19 | 23 | 26 | 26 | 22 | 16 | 10 | 6 |
| Afternoon | 5 | 7 | 11 | 16 | 19 | 23 | 26 | 26 | 22 | 16 | 10 | 6 |
| Night | 0 | 0 | 2 | 5 | 9 | 13 | 15 | 14 | 10 | 7 | 3 | 0 |
| Rain (mm) | 59 | 50 | 56 | 50 | 76 | 61 | 61 | 61 | 51 | 68 | 63 | 69 |
| Rainy days | 12 | 11 | 11 | 11 | 13 | 11 | 10 | 10 | 10 | 12 | 13 | 14 |
| Sun hours/day | 1.6 | 3.1 | 4.8 | 6.9 | 7.1 | 8.0 | 7.9 | 7.1 | 6.3 | 3.9 | 2.1 | 1.4 |
| Snow on the ground (cm) | 9 | 9 | 4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 8 |
| Afternoon | Afternoon | Night | Rain (mm) | Sun hours/day | |
|---|---|---|---|---|---|
| Jan | 5 | 5 | 0 | 59 | 1.6 |
| Feb | 7 | 7 | 0 | 50 | 3.1 |
| Mar | 11 | 11 | 2 | 56 | 4.8 |
| Apr | 16 | 16 | 5 | 50 | 6.9 |
| May | 19 | 19 | 9 | 76 | 7.1 |
| Jun | 23 | 23 | 13 | 61 | 8.0 |
| Jul | 26 | 26 | 15 | 61 | 7.9 |
| Aug | 26 | 26 | 14 | 61 | 7.1 |
| Sep | 22 | 22 | 10 | 51 | 6.3 |
| Oct | 16 | 16 | 7 | 68 | 3.9 |
| Nov | 10 | 10 | 3 | 63 | 2.1 |
| Dec | 6 | 6 | 0 | 69 | 1.4 |
Averages 1991–2020 (NASA POWER) for a cell about 55 km wide, brought to the altitude of the entrance (150 m) with the standard lapse rate. Not a forecast.
Recent years
Wet years, dry years.
Rain of each month as a share of the 1991–2020 average. A dry year means a lower river and hotter rock; a wet one, more water in the gorge.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2020 | 62% | 179% | 94% | 43% | 110% | 114% | 17% | 64% | 110% | 159% | 36% | 133% |
| 2021 | 153% | 91% | 61% | 64% | 121% | 182% | 185% | 40% | 108% | 68% | 67% | 118% |
| 2022 | 87% | 86% | 57% | 88% | 41% | 195% | 16% | 45% | 116% | 100% | 96% | 75% |
| 2023 | 114% | 17% | 136% | 123% | 50% | 106% | 96% | 108% | 72% | 165% | 166% | 102% |
| 2024 | 94% | 156% | 201% | 123% | 154% | 153% | 103% | 87% | 213% | 119% | 99% | 79% |
| 2025 | 123% | 49% | 35% | 41% | 23% | 64% | 53% | 56% | 108% | 57% | 65% | 36% |
130% or more: wet month 70% or less: dry month
Caves nearby.
Fosse Dionne
France
- —Depth
- —Galleries
- 150 mEntrance altitude
- 11 °CInside, all year
Caves of Arcy-sur-Cure
France · 33 km
- —Depth
- —Galleries
- 136 mEntrance altitude
- 11 °CInside, all year
Grotte du Renne
France · 33 km
- —Depth
- —Galleries
- 134 mEntrance altitude
- 11 °CInside, all year
Grotte des Fées
France · 163 km
- —Depth
- —Galleries
- 259 mEntrance altitude
- 11 °CInside, all year
Where these figures come from
| Name, type, published depth and length, visitors | Wikidata (Q3079408) · CC0 |
|---|---|
| The relief above, the entrance altitude, the section and the 3D model | Copernicus DEM GLO-30 · © DLR e.V., © Airbus Defence and Space GmbH, Copernicus/ESA |
| Climate | NASA POWER, 1991–2020 |
| Entrances, springs, sinkholes, opening hours and what is around | © OpenStreetMap contributors · ODbL |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
| Rivers, waterfalls, lakes, mountains, canyons, beaches and islands nearby | Coastya, Lakeyas, Peakyas, Cascadyas, Islandyas, Riveryas |
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, canyons, caves, dark skies, viewpoints, birdwatching or forests?
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