3D view drawn from Copernicus WorldDEM-30 (© DLR e.V., © Airbus Defence and Space GmbH, Copernicus/ESA) and Sentinel-2 cloudless 2016 by EOX IT Services GmbH, CC BY 4.0
Mountain in the Sierra Nevada of California, home to a ski resort
Mammoth Mountain is a mountain in the Sierra Nevada (United States). Its summit stands 3,371 m above sea level. Its prominence — how far it rises above the highest saddle linking it to a taller summit — is 502 m.
From the lowest point within 5 km (2,256 m), it rises 1,115 m. The steepest side is the north-east face: 22° on average over the first kilometre. In places the ground near the top reaches 45° — terrain for climbers, not walkers.
The nearest town is Mammoth Lakes, 6 km away at 2,402 m: 969 m below the summit.
Scores
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
6.4/10
Difficulty to the top
Alpine climb
Estimated from the slope: OpenStreetMap has no graded paths near the top.
Indicative only — never a safety assessment. Conditions change: ask local guides and check the forecast.
Ski score
7.3/10
Runs by difficulty
Snow season on the slopes (estimate)
Around 2,902 m, in the middle of the ski area: snow from November to May.
28 lifts · 5 km cross-country
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
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.
Snow
At the summit, snow from November to June (some years from October to June). Month by month below, at different heights on the way up.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Summit3,371 msnow from November to June (some years 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 some of the time | Snow on the ground all month | Snow on the ground all month |
Halfway up2,886 msnow from November to May | 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 | No snow | No snow | Snow on the ground all month | Snow on the ground all month |
Mammoth Lakes2,402 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 |
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
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 20 °C; on December nights it falls to about -15 °C. In 4 months of the year it stays below freezing at the top even in the afternoon. In July the 0 °C line climbs to about 6,440 m, above the summit: the top thaws on an average afternoon. Across the region, September is the driest month (7 mm) and December the wettest (104 mm).
| Month | Summit high °C | Summit low °C | Mammoth Lakes high °C | 0 °C line (m) | Rain & snow (mm) | Wet days | Sun h/day |
|---|---|---|---|---|---|---|---|
| January | -5 | -15 | 2 | 2,670 | 100 | 10 | 6.6 |
| February | -4 | -15 | 2 | 2,700 | 91 | 10 | 7.3 |
| March | -2 | -13 | 5 | 3,140 | 78 | 10 | 8.4 |
| April | 3 | -10 | 9 | 3,770 | 50 | 8 | 9.8 |
| May | 9 | -5 | 15 | 4,740 | 31 | 6 | 11.2 |
| June | 16 | 0 | 22 | 5,800 | 8 | 3 | 13.7 |
| July | 20 | 5 | 26 | 6,440 | 11 | 3 | 12.7 |
| August | 20 | 4 | 26 | 6,370 | 7 | 2 | 12.6 |
| September | 15 | 0 | 22 | 5,740 | 7 | 2 | 11.4 |
| October | 9 | -6 | 15 | 4,710 | 34 | 4 | 9.7 |
| November | 1 | -10 | 8 | 3,590 | 51 | 6 | 7.6 |
| December | -4 | -15 | 2 | 2,680 | 104 | 9 | 6.1 |
Estimate: the NASA POWER climate of a ~55 km cell (average height 2,620 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
Two cuts through the summit, 16 km long, from the 30 m Copernicus elevation model. Heights drawn 3× taller than lengths, so the shape can be seen.
Average slope of the first kilometre from the summit. The orange petal is the steepest side.
Around the mountain
Counted around the summit in OpenStreetMap, the map anyone can edit. The satellite plate shows 14 × 14 km.
N
5 km
Sentinel-2 cloudless 2016 (EOX, CC BY 4.0), 14 × 14 km, north up. Points © OpenStreetMap contributors.
Panorama Gondola Upper, Chair 22, Roller Coaster Express, Gold Rush Express and 21 more
Tamarack Cross-Country Ski Center, Mammoth Mountain
PCT - California Section H, John Muir Trail, Shadow Creek Trail, High Trail and 21 more
North Arete, Warming Wall, Crystal Crag Approach
Minaret Vista, Twin Lakes Scenic Viewpoint, Twin Falls view, Twin Falls and 6 more
Lake George Campground, Lake Mary Campground, Twin Lakes Campground, Coldwater Campground and 28 more
Our Peace of Mammoth, Krystal Villa East Rentals, 101 Great Escapes, Davison St Guest House and 81 more
4 path sections within 5 km, by SAC hiking scale (T1 easy walk … T6 difficult alpine).
OpenStreetMap is built by volunteers: a low number may just mean nobody has mapped it yet. Places © OpenStreetMap contributors (ODbL).
Photos
Recent years
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 | -5 | -4 | -2 | 3 | 9 | 16 | 20 | 20 | 15 | 9 | 1 | -4 |
| 2020 | +1.2 | +3.1 | −1.4 | +1.5 | +2.1 | +0.1 | +1.4 | +2.0 | +2.6 | +4.0 | +0.6 | +2.4 |
| 2021 | +2.3 | +0.3 | −0.9 | +3.9 | +2.3 | +3.3 | +1.1 | +1.8 | +2.5 | −2.8 | +3.4 | +0.6 |
| 2022 | −0.8 | +0.2 | +2.4 | +2.1 | +1.1 | +0.4 | +1.4 | +0.5 | +1.5 | +2.2 | −5.0 | −1.3 |
| 2023 | −2.6 | −3.0 | −5.0 | −3.5 | −2.1 | −4.7 | +0.4 | −1.8 | −1.5 | +0.8 | +0.4 | +4.2 |
| 2024 | +0.1 | −1.0 | −2.1 | +0.8 | +1.3 | +2.4 | +2.0 | −0.1 | +1.1 | +2.5 | −1.7 | +3.4 |
| 2025 | +2.2 | +1.4 | +0.3 | +1.6 | +2.0 | +1.2 | +0.1 | +0.6 | −0.8 | −0.3 | +1.9 | +5.3 |
+1 warmer than usual −1 cooler than usual
| Names, elevation, prominence | Wikidata (Q953984) · 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.
The family
Same idea, other landscapes: field atlases built on open data, month by month, in seven languages.
beaches
Find your beach: sea temperature, sun and swimming month by month.Visit 
lakes
Every lake on Earth: water temperature, ice, depth and the shore.Coming soonVisit 
mountains
Every summit in 3D: summit weather, the 0 °C line, huts and trails.You are here
waterfalls
Every waterfall: height, flow month by month and when it roars.Coming soonVisit 
islands
Every island from the sea up: size, sea temperature, ferries and 3D.Coming soonVisit 
rivers
Every river from source to sea: the journey, the flow and the basin in numbers.Coming soonVisit 
