Mountain·Switzerland / Italy

Castor

4,225m

Pennine Alps

Fuchs Robert · CC BY 3.0 · Wikimedia Commons

Elevation: 4,225m
Prominence: 156m
Isolation: 2.4km
Relief: 2,053mabove the lowest point within 5 km
Steepest slope: 56°within 1 km of the summit
Snow at the summit: All yearSee month by month ↓
Summit: 45.9208°N, 7.7931°E

Mountain in the Pennine Alps

Castor is a mountain in the Pennine Alps (Switzerland). Its summit stands 4,225 m above sea level. Its prominence — how far it rises above the highest saddle linking it to a taller summit — is 156 m, and the nearest higher ground is 2.4 km away.

From the lowest point within 5 km (2,172 m), it rises 2,053 m. The steepest side is the south-west face: 38° on average over the first kilometre. In places the ground near the top reaches 56° — terrain for climbers, not walkers.

The nearest town is Gressoney-La-Trinitè, 10 km away at 1,633 m: 2,592 m below the summit.

Castor for skiers and climbers

Two scores out of 10, built only from open data — every part is shown. They describe what the mountain offers, not how safe it is.

Hiking & mountaineering

8.8/10

Difficulty to the top

Alpine climb

Most path sections around the top are T5 on the SAC hiking scale. Glaciers around the top.

Indicative only — never a safety assessment. Conditions change: ask local guides and check the forecast.

2.5/2.541 waymarked routes and 129 path sections nearby
1.5/1.523 huts and shelters
2.0/22,592 m of ascent from the valley
0.9/1.5156 m of prominence
1.2/1.55 months with summit afternoons above −5 °C
0.6/1via ferratas, climbing and glaciers

Ski score

10.0/10

4.0/4409 km of downhill runs
1.5/1.598 ski lifts
1.5/1.52,056 m between the lowest and highest lift station
3.0/39 months of snow at about 2,857 m

Runs by difficulty

Beginner 4 km
Easy 91 km
Intermediate 253 km
Difficult 35 km
Freeride 26 km

Snow season on the slopes (estimate)

Around 2,857 m, in the middle of the ski area: snow from October to June (some years from September to June).

Snow on the ground all month
Snow some of the time
No snow
This month

98 lifts · lift stations from 1,829 to 3,885 m · 18 km cross-country

How these scores are made

Ski (where OpenStreetMap has skiing within 12 km): up to 4 points for the length of downhill runs (300 km or more = 4), 1.5 for the number of lifts (40+), 1.5 for the vertical between lift stations (1,500 m) and 3 for the snow season — a month counts when the estimated mean temperature at the height of the ski area is −1 °C or lower and snow falls or lies there (NASA POWER, 2001–2020). Hiking & mountaineering: up to 2.5 for waymarked routes and paths, 1.5 for huts, 2 for the ascent from the valley (2,000 m), 1.5 for prominence (3,000 m), 1.5 for the season (months with summit afternoons above −5 °C) and 1 for via ferratas, climbing and glaciers. OpenStreetMap is built by volunteers: where few things are mapped, a score can be lower than reality.

Plan your visit

Stay, climb and get there

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Snow

When there is snow on Castor

At the summit, snow all year round. Month by month below, at different heights on the way up.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Summit4,225 msnow all year round	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month
Halfway up2,929 msnow from October to June (some years from September to July)	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow some of the time	No snow	Snow some of the time	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month
Gressoney-La-Trinitè1,633 msnow from November to April	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month	No snow	No snow	No snow	No snow	No snow	No snow	Snow on the ground all month	Snow on the ground all month

Snow on the ground all month
Snow some of the time
No snow
This month

Estimate for a normal year: average temperature and precipitation from NASA POWER, carried to each height, in a simple model of snow building up and melting. In a given year snow can come earlier or stay longer. It does not replace the local snow and avalanche bulletin.

Summit weather

Castor, month by month

Not a forecast: long-term averages (1991–2020), carried up to the summit. The orange line is where an average afternoon reaches 0 °C; above the dashed blue line it freezes even at dawn.

On an average July afternoon the summit reaches about 2 °C; on January nights it falls to about -27 °C. In 9 months of the year it stays below freezing at the top even in the afternoon. In July the 0 °C line climbs to about 4,510 m, above the summit: the top thaws on an average afternoon. Across the region, February is the driest month (50 mm) and May the wettest (109 mm).

0 °C on an average afternoon 0 °C at dawn the summit

Month	Summit high °C	Summit low °C	Gressoney-La-Trinitè high °C	0 °C line (m)	Rain & snow (mm)	Wet days	Sun h/day
January	-18	-27	-2	1,370	63	11	3.3
February	-18	-27	-1	1,470	50	10	4.5
March	-15	-23	2	1,940	63	12	5.5
April	-10	-18	7	2,700	70	14	6.3
May	-5	-14	12	3,510	109	18	6.6
June	0	-9	17	4,250	97	17	8.5
July	2	-8	19	4,510	96	16	8.8
August	2	-8	18	4,450	99	15	7.9
September	-2	-12	15	3,880	68	14	6.9
October	-7	-15	10	3,200	72	13	5.0
November	-13	-21	4	2,200	91	14	3.1
December	-18	-26	-1	1,530	68	12	2.6

Estimate: the NASA POWER climate of a ~55 km cell (average height 2,251 m), adjusted to the summit by −6.5 °C per 1,000 m. Rain, wet days and sunshine are those of the region. Mountain weather changes fast — always check a local forecast. ★ = mildest months at the top.

Relief

The mountain in profile

Two cuts through the summit, 16 km long, from the 30 m Copernicus elevation model. Heights drawn 2× taller than lengths, so the shape can be seen.

West – east

South – north

Steepness by direction

Average slope of the first kilometre from the summit. The orange petal is the steepest side.

Around the mountain

Huts, lifts and trails around Castor

Counted around the summit in OpenStreetMap, the map anyone can edit. The satellite plate shows 14 × 14 km.

A lift reaches 3,885 m — just 340 m below the summit.

23mountain huts and shelters
Rifugio Gabiet (2,370 m), Rifugio Ottorino Mezzalama (3,036 m), Rifugio Guide d'Ayas (3,388 m), Rifugio G.B. Ferraro (2,077 m) and 19 more
40cable cars, gondolas, chairlifts and rack railways
Gant - Hohtälli, Furi - Trockener Steg, Gifthittli, Furgg - Sandiger Boden and 36 more
7ski areas
Antagnod, Monterosa Ski, Zermatt - Breuil-Cervinia, Macugnaga - Belvedere and 3 more
41waymarked hiking routes
Tour du Cervin, Le sorgenti del Lys, Itinerario 8B Pian di Verra Inferiore - Résy, Ru Courtod and 37 more
—via ferratas
1climbing crags and routes
Falesia Pian delle rane
33named glaciers
Triftjigletscher, Theodulgletscher, Ghiacciaio della Sesia, Ghiacciaio di Indren and 29 more
31viewpoints
Gornergrat and 30 more
1campsites
Tschaval
44hotels, B&Bs and chalets
Hotel Breithorn, Hotel Castor, Igludorf, Hotel California and 40 more
77restaurants and cafés

How hard are the paths?

129 path sections within 5 km, by SAC hiking scale (T1 easy walk … T6 difficult alpine).

T2T3T4T5T6

T2 mountain hiking
T3 demanding mountain hiking
T4 alpine hiking
T5 demanding alpine hiking
T6 difficult alpine hiking

Towns at the foot

Gressoney-La-Trinitè10 km · 1,633 m
Zermatt12 km · 1,608 m
Alagna Valsesia14 km · 1,191 m
Paquier14 km · 1,593 m
Valtournenche14 km · 1,518 m
Ayas14 km · 1,708 m
Antagnod14 km · 1,708 m
Staffa14 km · 1,327 m

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OpenStreetMap is built by volunteers: a low number may just mean nobody has mapped it yet. Places © OpenStreetMap contributors (ODbL).

Photos

Seen by climbers and visitors

Castor & Pollux from Gornergrat 14 04 2024 — Paradise Chronicle · CC BY-SA 4.0

Castor and Pollux as seen from Gornergrat, Wallis, Switzerland, 2012 August — Ximonic (Simo Räsänen) · CC BY-SA 4.0

Recent years

How each month compared at the summit

Afternoon high at the summit (estimate). The first row is the reference, the 1991–2020 average in °C; the years show only the difference.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
1991–2020 average	-18	-18	-15	-10	-5	0	2	2	-2	-7	-13	-18
2020	+2.3	+3.1	+0.5	+2.0	+2.1	−1.8	+1.0	+0.8	+1.1	−2.4	+3.5	±0.0
2021	−1.7	+2.9	−0.3	−0.5	−2.5	+1.0	−0.2	−0.4	+1.6	−0.3	+0.3	+1.5
2022	+1.3	+1.8	+1.0	+1.5	+3.0	+2.4	+3.2	+2.1	−0.4	+3.6	+0.5	+1.4
2023	+0.3	+2.2	+2.1	−0.3	+0.4	+0.7	+1.3	+0.9	+4.1	+2.4	−0.9	+2.2
2024	+2.2	+4.1	+1.5	−1.5	−0.5	−0.3	+2.1	+2.9	−2.0	+0.8	+2.7	+1.6
2025	+2.1	+2.6	+1.2	+2.3	+0.7	+4.0	−0.7	+1.4	+0.5	−0.4	+0.3	+2.5

+1 warmer than usual −1 cooler than usual

Nearby

More mountains nearby

3,883 mKlein Matterhorn

Switzerland5 km away

About these numbers

Names, elevation, prominence	Wikidata (Q30446) · CC0
Relief, 3D view, profiles	Copernicus DEM GLO-30 · © DLR e.V., © Airbus Defence and Space GmbH, Copernicus/ESA
Climate	NASA POWER, 1991–2020 · CC BY 4.0
Around the mountain	© OpenStreetMap contributors · ODbL
Images	EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons

Every figure is an average, an estimate or a count from a public dataset. Licences and methods: data sources.

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