Mountain·Italy / France

Aiguille de Bionnassay

4,052m

Mont Blanc massif

WikiSephiroth · CC BY-SA 3.0 · Wikimedia Commons

Elevation: 4,052m
Prominence: 164m
Isolation: 1.8km
Relief: 2,589mabove the lowest point within 5 km
Steepest slope: 62°within 1 km of the summit
Snow at the summit: All yearSee month by month ↓
Summit: 45.8361°N, 6.8189°E

Mountain in the Mont-Blanc massif in the Alps

Aiguille de Bionnassay is a mountain in the Mont Blanc massif (Italy). Its summit stands 4,052 m above sea level. Its prominence — how far it rises above the highest saddle linking it to a taller summit — is 164 m, and the nearest higher ground is 1.8 km away.

From the lowest point within 5 km (1,463 m), it rises 2,589 m. The steepest side is the north face: 46° on average over the first kilometre. In places the ground near the top reaches 62° — terrain for climbers, not walkers.

The nearest town is Les Houches, 6 km away at 1,038 m: 3,014 m below the summit.

Aiguille de Bionnassay 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

9.2/10

Difficulty to the top

Alpine climb

Most path sections around the top are T6 on the SAC hiking scale. Glaciers around the top.

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

2.5/2.5125 waymarked routes and 235 path sections nearby
1.5/1.525 huts and shelters
2.0/23,014 m of ascent from the valley
1.0/1.5164 m of prominence
1.2/1.55 months with summit afternoons above −5 °C
1.0/1via ferratas, climbing and glaciers

Ski score

10.0/10

4.0/4370 km of downhill runs
1.5/1.5116 ski lifts
1.5/1.52,376 m between the lowest and highest lift station
3.0/39 months of snow at about 2,589 m

Runs by difficulty

Beginner 26 km
Easy 118 km
Intermediate 119 km
Difficult 42 km
Freeride 64 km

Snow season on the slopes (estimate)

Around 2,589 m, in the middle of the ski area: snow from October to June.

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

116 lifts · lift stations from 1,401 to 3,777 m · 27 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 Aiguille de Bionnassay

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
Summit4,052 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 up2,545 msnow from October to June	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	No snow	No snow	No snow	Snow on the ground all month	Snow on the ground all month	Snow on the ground all month
Les Houches1,038 msnow from December 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	No snow	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

Aiguille de Bionnassay, 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 3 °C; on January nights it falls to about -26 °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 4,480 m, above the summit: the top thaws on an average afternoon. Across the region, April is the driest month (74 mm) and May the wettest (117 mm).

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

Month	Summit high °C	Summit low °C	Les Houches high °C	0 °C line (m)	Rain & snow (mm)	Wet days	Sun h/day
January	-18	-26	2	1,330	107	12	3.3
February	-17	-26	2	1,410	77	11	4.5
March	-14	-22	6	1,900	94	13	5.5
April	-8	-17	12	2,820	74	13	6.3
May	-3	-13	16	3,540	117	18	6.6
June	1	-9	21	4,210	105	16	8.5
July	3	-7	22	4,480	103	15	8.8
August	3	-8	22	4,450	105	14	7.9
September	-1	-11	19	3,900	76	13	6.9
October	-5	-15	14	3,270	86	13	5.0
November	-12	-20	8	2,220	94	14	3.1
December	-16	-24	3	1,560	110	14	2.6

Estimate: the NASA POWER climate of a ~55 km cell (average height 1,714 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. True scale: no vertical exaggeration.

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 Aiguille de Bionnassay

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

A lift reaches Aiguille du Midi 2 at 3,777 m — just 275 m below the summit.

25mountain huts and shelters
Chalet du CAF Contamines (1,164 m), Refuge du Fioux, Auberge du Truc (1,750 m), Refuge de Tré la Tête and 21 more
23cable cars, gondolas, chairlifts and rack railways
TPH Plan de l'Aiguille, Bertolini, Plan de la Gabba, Youla and 19 more
14ski areas
Tremplin du Grepon, Courmayeur, Les Houches (Chamonix), Les Contamines and 10 more
125waymarked hiking routes
Pont Combal - Bivacco Rainetto, Col de Tricot, Tour Du Mont Blanc - Variante du Col de Tricot, Tour du Mont Blanc - Itinéraire principal and 121 more
2via ferratas
Via corda
37climbing crags and routes
La Duchère, Aiguille des 2 Aigles - Secteur du Plan, Aiguille du Midi - Versant Nord, Aiguille des Pèlerins - Secteur du Plan and 33 more
46named glaciers
Glacier de Bionnassay, Glacier de Taconnaz, Ghiacciaio della Lex Blanche, Ghiacciaio del Freney and 42 more
44viewpoints
Mont Blanc / Monte Bianco, Chalet des Pyramides, La Jonction, Col de Tricot and 40 more
17campsites
Aire de bivouac tolérée de Miage, Hobo Camping, Camping de Tête Rousse, Camping Les Marmottes and 13 more
112hotels, B&Bs and chalets
Le Morgane, Le Refuge des Aiglons, Auberge de jeunesse de Chamonix, Hôtel du Clocher and 108 more
164restaurants and cafés

How hard are the paths?

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

T1T2T3T4T5T6

T1 hiking
T2 mountain hiking
T3 demanding mountain hiking
T4 alpine hiking
T5 demanding alpine hiking
T6 difficult alpine hiking

Towns at the foot

Les Houches6 km · 1,038 m
Les Contamines-Montjoie7 km · 1,176 m
Saint-Gervais-les-Bains10 km · 840 m
Chamonix-Mont-Blanc11 km · 1,060 m
Courmayeur12 km · 1,224 m
Passy14 km · 654 m
Combloux15 km · 957 m
Domancy15 km · 562 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

Aiguille-du-Midi-summer — Martin Janner · CC BY-SA 3.0

Aiguille de Bionassay — Rossoila · CC BY-SA 3.0

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	-17	-14	-8	-3	1	3	3	-1	-5	-12	-16
2020	+2.0	+2.4	+0.8	+3.6	+1.9	−2.1	+0.7	+1.0	+1.1	−2.8	+3.2	−0.5
2021	−1.7	+1.8	+0.8	−0.9	−3.0	+1.3	−0.8	−1.3	+1.5	+0.2	+0.1	+0.8
2022	+0.8	+1.4	+1.2	+0.8	+2.9	+3.2	+4.4	+3.7	−0.2	+3.5	+0.8	+1.3
2023	+0.5	+4.0	+3.2	−1.1	+0.5	+1.5	+1.4	+1.9	+4.9	+2.9	−1.5	+1.2
2024	+1.7	+3.3	+3.1	−0.1	−0.4	−0.1	+1.6	+3.0	−1.4	+1.4	+1.9	+0.7
2025	+1.9	+2.0	+2.8	+3.2	+0.3	+3.8	−0.7	+2.2	+0.2	−0.9	+0.2	+2.3

+1 warmer than usual −1 cooler than usual

Nearby

More mountains nearby

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4,248 mMont Blanc du Tacul

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About these numbers

Names, elevation, prominence	Wikidata (Q30493) · 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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