More climate-resilient than 9% of Western resorts · 16% of all North American resorts
#139 of 152 in the West · #184 of 220 overall
What goes into it, compared with Western resorts:
* A ranking against the North American resorts we rate, not a grade out of 100: 100 = most resilient in the field, 50 = middle of the pack. Higher scores mean the resort's terrain and weather profile are more resilient in preserving winter conditions, both today and in a future of warmer temperatures.
Less rain risk than 19% of Western resorts · 27% of all North American resorts
#122 of 152 in the West · #160 of 220 overall
About 23.8% of winter precipitation falls as rain today, about 45% at +2°C.
How well Mt Lemmon's winter precipitation holds up as snow rather than rain. We rebuilt 40 winters of hourly weather at the resort's base, mid-mountain and peak, then estimated whether each hour's precipitation fell as rain or snow from temperature and humidity. To see what warming would do, we re-ran the same winters 1°C and 2°C warmer. The score is a ranking, not a grade: 100 = least rain risk in the field, 50 = middle of the pack.
When might +1°C and +2°C happen?
Roughly +1°C by the mid 2030s and +2°C around 2050 for North American ski country — sooner if emissions keep rising, possibly never if they fall fast. It's already about 0.7°C warmer than the 1986–2026 average these numbers start from.
These are local winter warming above the average of the 1986–2026 winters we rebuilt (centered around 2006), not the global “1.5°C / 2°C above pre-industrial” targets, which start from the 1800s. The world has warmed about 1.37°C since pre-industrial times and is warming about 0.27°C per decade (Indicators of Global Climate Change 2025); North America's land warms roughly 1.5× faster than that, fastest in winter (U.S. National Climate Assessment). A rough guide, not a forecast: real timing depends on future emissions and varies by region and year.
| 1986–2006 | 2006–2026 | +1°C*(mid 2030s) | +2°C*(2050) | |
|---|---|---|---|---|
| 9,160' Peak | 13.5% | 15.6% | 22.6% | 32.7% |
| 8,680' Mid | 21.1% | 22.5% | 31.7% | 42.8% |
| 8,200' Base | 30.6% | 30.7% | 41.7% | 53.0% |
The first two columns are the real observed weather record, split into two equal halves. * The +1°C and +2°C columns are stress tests: the full observed record replayed with that much warming added, so they show sensitivity to warming, not a forecast for a specific year. Elevations are rounded to the nearest 10 ft.
Full rain data, season-by-season history & resort comparisons →
How El Niño and La Niña winters affect Mt Lemmon →
More naturally skiable days than 4% of Western resorts · 10% of all North American resorts
#146 of 152 in the West · #199 of 220 overall
64 of 181 possible days today (Nov–Apr), about 28 at +2°C.
How many days a season Mt Lemmon has enough natural snow to ski, November through April. We simulated the snowpack day by day for 40 winters at the base, mid-mountain and peak — snow piling up, melting on warm days, and getting eaten away by rain — then ran the same winters 1°C and 2°C warmer.
When might +1°C and +2°C happen?
Roughly +1°C by the mid 2030s and +2°C around 2050 for North American ski country — sooner if emissions keep rising, possibly never if they fall fast. It's already about 0.7°C warmer than the 1986–2026 average these numbers start from.
These are local winter warming above the average of the 1986–2026 winters we rebuilt (centered around 2006), not the global “1.5°C / 2°C above pre-industrial” targets, which start from the 1800s. The world has warmed about 1.37°C since pre-industrial times and is warming about 0.27°C per decade (Indicators of Global Climate Change 2025); North America's land warms roughly 1.5× faster than that, fastest in winter (U.S. National Climate Assessment). A rough guide, not a forecast: real timing depends on future emissions and varies by region and year.
| Today | +1°C*(mid 2030s) | +2°C*(2050) | |
|---|---|---|---|
| 9,160' Peak | 79 | 67 | 53 |
| 8,680' Mid | 67 | 53 | 31 |
| 8,200' Base | 54 | 31 | 12 |
Warmer winters don't just turn some snowfall into rain. Rain also eats away the snow that's already on the ground, in four ways:
Our model simulates all four, using a simplified version of the snowmelt model the U.S. National Weather Service uses for river forecasting.
Natural snow only — no snowmaking or grooming, so resorts that make a lot of snow stay open longer than these numbers. “Skiable” means at least 3 inches of snow-water in the snowpack (roughly a 12–18 inch settled base). Snowfall is scaled to match Mt Lemmon's average snowfall. Melt follows the sun on Mt Lemmon's actual runs: shady, north-facing slopes hold snow longer than sunny ones. * Stress tests, not forecasts: the same winters replayed warmer. Checked against 40 years of real snowpack measurements at 105 SNOTEL stations across the West, where it's typically within about a week of the real season length.
Terrain holds snow better than 77% of Western resorts · 74% of all North American resorts
#36 of 150 in the West · #57 of 216 overall
Mt Lemmon's runs get 25% less winter sun than the same slopes would facing every direction equally. Typical resort: 17% less.
How well Mt Lemmon's runs are oriented to hold onto snow. North-facing slopes get less direct sun and keep snow longer; south-facing slopes lose it faster. We measured the direction and steepness of 21 mapped runs and compared the sunshine they receive with what the same slopes would get if they faced every direction equally, so this score reflects terrain orientation only, not latitude or elevation (those are covered by the rain score above).
Share of mapped terrain facing each direction. Trail data © OpenStreetMap contributors via OpenSkiMap.