upslopeAugust 28, 2026 New England rain event — forecast vs. what fell
event hit rate 39%
MAE 0.17″
31 mountains scored
On August 28, 2026, 9 of 31 scored New England ski resorts recorded measurable rain, peaking at 0.36″ near Black Mountain. upslope’s day-before forecasts verified at a 39% event hit rate with a mean absolute error of 0.17″ across 31 mountains. Ground truth: median of CoCoRaHS volunteer gauges near each resort (min 2 reporting).
Mountain by mountain
| Resort | Forecast | Measured | Error | Call |
|---|---|---|---|---|
| Black MountainNH | 0.2″ | 0.36″ | -0.16″ | ✓ |
| SaddlebackME | 0.14″ | 0.32″ | -0.18″ | ✓ |
| SugarloafME | 0.06″ | 0.32″ | -0.26″ | ✗ |
| OkemoVT | 0.3″ | 0.15″ | +0.15″ | ✓ |
| BromleyVT | 0.16″ | 0.13″ | +0.03″ | ✓ |
| AttitashNH | 0.16″ | 0.12″ | +0.04″ | ✓ |
| CranmoreNH | 0.13″ | 0.12″ | +0.01″ | ✓ |
| KillingtonVT | 0.63″ | 0.12″ | +0.51″ | ✓ |
| Mount SnowVT | 0.19″ | 0.11″ | +0.08″ | ✓ |
| PicoVT | 0.55″ | 0.09″ | +0.46″ | ✗ |
| Magic MountainVT | 0.15″ | 0.07″ | +0.08″ | ✗ |
| StrattonVT | 0.18″ | 0.07″ | +0.11″ | ✗ |
| Berkshire EastMA | 0.22″ | 0.03″ | +0.19″ | ✗ |
| Bretton WoodsNH | 0.15″ | 0.03″ | +0.12″ | ✗ |
| Mad River GlenVT | 0.26″ | 0.03″ | +0.23″ | ✗ |
| SugarbushVT | 0.31″ | 0.03″ | +0.28″ | ✗ |
| WildcatNH | 0.19″ | 0.03″ | +0.16″ | ✗ |
| BurkeVT | 0.23″ | 0.01″ | +0.22″ | ✗ |
| CannonNH | 0.23″ | 0.01″ | +0.22″ | ✗ |
| Jay PeakVT | 0.27″ | 0.01″ | +0.26″ | ✗ |
| LoonNH | 0.31″ | 0.01″ | +0.3″ | ✗ |
| Bolton ValleyVT | 0.23″ | — | +0.23″ | ✗ |
| CrotchedNH | 0.02″ | — | +0.02″ | ✓ |
| GunstockNH | 0.09″ | — | +0.09″ | ✓ |
| Mount SunapeeNH | 0.02″ | — | +0.02″ | ✓ |
| Pats PeakNH | 0.02″ | — | +0.02″ | ✓ |
| RaggedNH | 0.11″ | — | +0.11″ | ✗ |
| Smugglers' NotchVT | 0.17″ | — | +0.17″ | ✗ |
| StoweVT | 0.19″ | — | +0.19″ | ✗ |
| WachusettMA | 0.12″ | — | +0.12″ | ✗ |
| Waterville ValleyNH | 0.35″ | — | +0.35″ | ✗ |
Scoring fix, Oct 8, 2026: earlier versions compared each gauge report (7am-to-7am) against the forecast for the wrong calendar day; all history was rescored under the corrected rule.
Forecast = upslope's NWS-based rain forecast for the same 7am-to-7am window the gauges measure, from the last run before that window opened. ✓ = correctly called rain above/below 0.1″. Positive error = over-forecast.