Portugal Beatriznog10 · CC BY-SA 3.0
The cut
34 metres, to scale.
A slice through Boca do Inferno where it is deepest and narrowest, measured on the Copernicus relief model every 30 m. Same scale as the landmark standing on the floor.
Standing on the floor, to scale: a person · 1.8 m · a two-storey house · 9.0 m
Depth is measured to the lower rim; the width is from rim to rim. A 30 m relief model smooths the narrowest walls, so a slot canyon reads shallower than it is.
34m
Depth
measured on the 30 m relief model
6.6km
Rim to rim
measured on the 30 m relief model
5°
Steepest wall
average over 300 m, from the relief
0m
Floor altitude
Rim to floor
Afternoons, up top and down below.
In August the afternoon reaches 23 °C. The best months to hike are from May to July and from September to October. The wettest months are in March and from October to January.
- 15°14°Jan
- 15°14°Feb
- 16°16°Mar
- 17°17°Apr
- 19°19°May
- 21°21°Jun
- 22°22°Jul
- 23°23°Aug
- 22°22°Sep
- 21°20°Oct
- 18°17°Nov
- 16°15°Dec
Afternoon highs, 1991–2020 averages (NASA POWER) brought to the altitude of the rim and of the floor with the standard lapse rate (6.5 °C per 1 000 m). Shade, wind and rock change this on the day. Not a forecast.
Tourist attraction in Cascais, Portugal
Boca do Inferno is a ravine in Portugal. The relief model measures 34 m from the floor to the lower rim, and 58 m to the higher one. Rim to rim it is 6.6 km wide where the cut was taken.
Getting there.
- Cascaisnearest town · 1.0 km in a straight line
- Parking 380 m awaynearest car park in OpenStreetMap, straight line
- Viewpointsnearest viewpoint · 0.2 km from the floor
- Cascais Airport (CAT)nearest airport with scheduled flights · 8 km in a straight lineCar hire at LIS airport (Lisbon)Discover Cars · sponsored link↗
- From May to July and from September to Octoberbest months to hike (estimate)
Plan the visit
Guided hikes, 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 the sky.
The canyon from above, with the relief shaded, the line of the cut, the river and what people have mapped around it.
N
4 km
Sentinel-2 cloudless 2016 (EOX, CC BY 4.0), 14 × 14 km, north up. The line is the cut above. Points © OpenStreetMap contributors.
Around the canyon.
- 14viewpoints within 5 kmAnfiteatro Natural da Pedra do Sal and 13 more
- 6marked hiking routes within 4 kmCaminho do Atlântico (Troço Cabo Raso - Abano), Rota do Cabo Raso, Trilho das Areias and 3 more
- 12climbing crags within 3 kmEscola de Escalada da Guia, Guia Nova, Cantinho dos Teimosos and 9 more
- 22footbridges and suspension bridges within 3 kmPasseio Rainha Dona Maria Pia, Ponte, Trilho das Vinhas and 19 more
- 4rafting, canoe, kayak or canyoning spots within 4 km
- 1caves within 3 km
- 152car parks within 3 km
- 12information boards and visitor centres within 4 km
- 143bus stops within 2 km
- 1campsites within 8 kmOrbitur Guincho
- 88hotels and guesthouses within 8 kmVila Galé Estoril, Hotel Alvorada, Pestana Sintra Golf and 85 more
- 379restaurants and cafés within 4 km
- via ferrata routes within 4 km
- swimming spots within 3 km
- named waterfalls within 4 km
Counted in OpenStreetMap, the map anyone can edit, around the floor of the canyon. A low number may just mean nobody has mapped it yet. © OpenStreetMap contributors (ODbL).
Towns nearby
- Cascais1.0 km in a straight line
- Cobre2.5 km in a straight line
- Alvide2.7 km in a straight line
- Monte Estoril2.8 km in a straight line
- Estoril3.3 km in a straight line
- Alcabideche5.1 km in a straight line
- Alcoitão5.8 km in a straight line
- Parede6.7 km in a straight line
In our other atlases
What else is around Boca do Inferno.
The river that carved it, the waterfalls inside it, the mountains on the rim, the lakes, beaches and island nearby — from our six sister atlases, each with its own figures.
Peakyas10 mountains within 15 km
Coastya65 beaches within 15 kmFigures from the sister sites' databases (Wikidata, HydroATLAS, GeoNames, NOAA, OpenStreetMap). Links open when each site is online.
Month by month
The weather, at the floor and at the rim.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Afternoon · floor | 15 | 15 | 16 | 17 | 19 | 21 | 22 | 23 | 22 | 21 | 18 | 16 |
| Afternoon · rim | 14 | 14 | 16 | 17 | 19 | 21 | 22 | 23 | 22 | 20 | 17 | 15 |
| Night · rim | 11 | 11 | 12 | 13 | 14 | 16 | 17 | 18 | 18 | 16 | 14 | 12 |
| Rain (mm) | 65 | 51 | 60 | 54 | 31 | 11 | 3 | 6 | 25 | 79 | 92 | 64 |
| Rainy days | 10 | 8 | 9 | 9 | 7 | 2 | 1 | 1 | 5 | 10 | 12 | 11 |
| Sun hours/day | 4.8 | 6.2 | 7.3 | 9.0 | 10.6 | 11.1 | 11.5 | 10.9 | 9.1 | 6.8 | 5.3 | 4.8 |
| Afternoon · floor | Afternoon · rim | Night · rim | Rain (mm) | Sun hours/day | |
|---|---|---|---|---|---|
| Jan | 15 | 14 | 11 | 65 | 4.8 |
| Feb | 15 | 14 | 11 | 51 | 6.2 |
| Mar | 16 | 16 | 12 | 60 | 7.3 |
| Apr | 17 | 17 | 13 | 54 | 9.0 |
| May | 19 | 19 | 14 | 31 | 10.6 |
| Jun | 21 | 21 | 16 | 11 | 11.1 |
| Jul | 22 | 22 | 17 | 3 | 11.5 |
| Aug | 23 | 23 | 18 | 6 | 10.9 |
| Sep | 22 | 22 | 18 | 25 | 9.1 |
| Oct | 21 | 20 | 16 | 79 | 6.8 |
| Nov | 18 | 17 | 14 | 92 | 5.3 |
| Dec | 16 | 15 | 12 | 64 | 4.8 |
Averages 1991–2020 (NASA POWER) for a cell about 55 km wide, brought to the floor (0 m) and the rim (58 m) with the standard lapse rate. Not a forecast.
Photographs
Seen from the trail.
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 | 63% | 11% | 92% | 236% | 202% | 53% | — | 90% | 108% | 164% | 133% | 117% |
| 2021 | 59% | 162% | 37% | 120% | 53% | 125% | — | 63% | 135% | 52% | 18% | 102% |
| 2022 | 11% | 67% | 157% | 82% | 19% | 125% | — | 15% | 208% | 91% | 64% | 302% |
| 2023 | 66% | 32% | 40% | 19% | 44% | 144% | — | 15% | 252% | 157% | 65% | 49% |
| 2024 | 140% | 106% | 159% | 39% | 18% | 231% | — | 32% | 37% | 98% | 58% | 22% |
| 2025 | 164% | 168% | 239% | 178% | 87% | 19% | — | 15% | 48% | 42% | 148% | 222% |
130% or more: wet month 70% or less: dry month
Where these figures come from
| Name, type, published depth and length | Wikidata (Q888949) · CC0 |
|---|---|
| The cut: depth, width, wall and 3D model | Copernicus DEM GLO-30 · © DLR e.V., © Airbus Defence and Space GmbH, Copernicus/ESA |
| Climate | NASA POWER, 1991–2020 |
| Viewpoints, trails, bridges and the river line | © OpenStreetMap contributors · ODbL |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
| Rivers, waterfalls, mountains, lakes, 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
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