United Kingdom Sentinel-2 cloudless 2016 by EOX IT Services GmbH (contains modified Copernicus Sentinel data), CC BY 4.0, with relief shading from Copernicus WorldDEM-30
The descent
The entrance, at 351 m.
The real relief above Ogof Ffynnon Ddu, 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.
351m
Entrance altitude
from the 30 m relief model
8°C
Inside, all year
the yearly average outside, at the entrance
158m
Rock above
the highest point within 1.5 km
Inside and outside
8 °C inside, all year.
Deep inside, a cave keeps the average temperature of the year outside: about 8 °C here, in January and in August. In July the afternoon reaches 18 °C at the entrance, 10 °C warmer than inside: take a jacket.
- 5°1°Jan
- 5°0°Feb
- 7°1°Mar
- 11°3°Apr
- 14°6°May
- 17°9°Jun
- 18°10°Jul
- 18°10°Aug
- 16°8°Sep
- 12°6°Oct
- 8°4°Nov
- 6°2°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.
Cave in the Upper Swansea Valley in South Wales
Ogof Ffynnon Ddu is a cave in United Kingdom. The entrance is at 351 m.
Getting there.
- Wild cave: only with caving equipmentNo paths or lights inside. Go only with a caving club or a qualified guide.
- Seven Sistersnearest town · 7.5 km in a straight line
- Viewpointsnearest viewpoint · 2.2 km from the entrance
- Cardiff International Airport (CWL)nearest airport with scheduled flights · 52 km in a straight lineCar hire at CWL airport (Cardiff)Discover 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.
- 5other cave entrances within 3 kmOgof y nos hir, Ogof Ffynnon Ddu (OFD) top entrance, Cwm Dwr (OFD), Dan-Yr-Ogof and 2 more
- 2sinkholes within 3 kmPwll y Cawr shake hole
- 1viewpoints within 3 km
- 3marked hiking routes within 3 kmBeacons Way, Cambrian Way, Henrhyd Falls and Nant Llech walk, East Wales
- 2named waterfalls within 4 kmSgwd Ddu, Henrhyd Falls
- 7car parks within 2 km
- 10bus stops within 2 km
- 6campsites within 8 kmBrecon Beacons Camping & Caravan Park, Cae Glas Camping, Bryn Bwch and 3 more
- 6hotels and guesthouses within 8 kmBunkhouse Wales, Clyngwyn Farm, Heronstone Holiday Retreat, Ynyscedwyn Arms Hotel and 3 more
- 2restaurants and cafés within 3 km
- springs within 2 km
- caving clubs and spots within 15 km
- climbing crags within 3 km
- information boards and visitor centres within 3 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
- Seven Sisters7.5 km in a straight line
- Glyn-neath9.0 km in a straight line
- Ystalyfera10 km in a straight line
- Crynant12 km in a straight line
- Resolven13 km in a straight line
- Hirwaun14 km in a straight line
- Brynamman14 km in a straight line
- Aberdare19 km in a straight line
In our other atlases
What else is around Ogof Ffynnon Ddu.
The river at the entrance, the waterfalls, the lakes, the mountains and volcanoes above, the canyons, beaches and islands nearby — from our other atlases.
Lakeyas1 lakes within 10 km
Peakyas31 mountains within 10 kmFigures 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 | 5 | 7 | 11 | 14 | 17 | 18 | 18 | 16 | 12 | 8 | 6 |
| Afternoon | 5 | 5 | 7 | 11 | 14 | 17 | 18 | 18 | 16 | 12 | 8 | 6 |
| Night | 1 | 0 | 1 | 3 | 6 | 9 | 10 | 10 | 8 | 6 | 4 | 2 |
| Rain (mm) | 128 | 99 | 90 | 71 | 85 | 93 | 102 | 107 | 89 | 131 | 134 | 141 |
| Rainy days | 19 | 16 | 16 | 15 | 15 | 15 | 17 | 18 | 16 | 18 | 20 | 19 |
| Sun hours/day | 1.5 | 2.5 | 4.0 | 5.7 | 6.4 | 6.3 | 5.9 | 5.1 | 4.7 | 2.8 | 1.7 | 1.2 |
| Snow on the ground (cm) | 6 | 6 | 4 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 4 |
| Afternoon | Afternoon | Night | Rain (mm) | Sun hours/day | |
|---|---|---|---|---|---|
| Jan | 5 | 5 | 1 | 128 | 1.5 |
| Feb | 5 | 5 | 0 | 99 | 2.5 |
| Mar | 7 | 7 | 1 | 90 | 4.0 |
| Apr | 11 | 11 | 3 | 71 | 5.7 |
| May | 14 | 14 | 6 | 85 | 6.4 |
| Jun | 17 | 17 | 9 | 93 | 6.3 |
| Jul | 18 | 18 | 10 | 102 | 5.9 |
| Aug | 18 | 18 | 10 | 107 | 5.1 |
| Sep | 16 | 16 | 8 | 89 | 4.7 |
| Oct | 12 | 12 | 6 | 131 | 2.8 |
| Nov | 8 | 8 | 4 | 134 | 1.7 |
| Dec | 6 | 6 | 2 | 141 | 1.2 |
Averages 1991–2020 (NASA POWER) for a cell about 55 km wide, brought to the altitude of the entrance (351 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 | 106% | 282% | 118% | 71% | 20% | 160% | 112% | 138% | 78% | 150% | 93% | 165% |
| 2021 | 153% | 160% | 93% | 24% | 233% | 47% | 88% | 68% | 114% | 166% | 39% | 107% |
| 2022 | 42% | 171% | 52% | 60% | 86% | 83% | 48% | 38% | 121% | 105% | 136% | 79% |
| 2023 | 112% | 25% | 194% | 136% | 40% | 51% | 139% | 99% | 129% | 123% | 104% | 168% |
| 2024 | 93% | 183% | 155% | 174% | 101% | 48% | 99% | 83% | 137% | 98% | 73% | 93% |
| 2025 | 107% | 96% | 30% | 105% | 49% | 125% | 58% | 51% | 188% | 93% | 135% | 134% |
130% or more: wet month 70% or less: dry month
Caves nearby.
Ogof Ffynnon Ddu
United Kingdom
- —Depth
- —Galleries
- 351 mEntrance altitude
- 8 °CInside, all year
Dan yr Ogof
United Kingdom · 2 km
- —Depth
- 17 kmGalleries
- 247 mEntrance altitude
- 9 °CInside, all year
Cathole Cave
United Kingdom · 41 km
- —Depth
- —Galleries
- 37 mEntrance altitude
- 11 °CInside, all year
Gough's Cave
United Kingdom · 86 km
- —Depth
- —Galleries
- 67 mEntrance altitude
- 10 °CInside, all year
Where these figures come from
| Name, type, published depth and length, visitors | Wikidata (Q1470850) · 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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