upslope

October 3, 2026 New England rain event — forecast vs. what fell

event hit rate 94% MAE 0.03″ 32 mountains scored

On October 3, 2026, 12 of 32 scored New England ski resorts recorded measurable rain, peaking at 0.48″ near Jay Peak. upslope’s day-before forecasts verified at a 94% event hit rate with a mean absolute error of 0.03″ across 32 mountains. Ground truth: median of CoCoRaHS volunteer gauges near each resort (min 2 reporting).

Mountain by mountain

Resort Forecast Measured Error Call
Jay PeakVT0.4″0.48″-0.08″✓
Smugglers' NotchVT0.31″0.44″-0.13″✓
StoweVT0.29″0.37″-0.08″✓
BurkeVT0.07″0.36″-0.29″✗
Bolton ValleyVT0.26″0.24″+0.02″✓
Mad River GlenVT0.22″0.19″+0.03″✓
SugarbushVT0.18″0.18″0.0″✓
CannonNH0.12″0.12″0.0″✓
Bretton WoodsNH0.11″0.1″+0.01″✓
KillingtonVT0.22″0.1″+0.12″✓
PicoVT0.19″0.1″+0.09″✓
WildcatNH0.05″0.1″-0.05″✗
StrattonVT0.06″0.06″0.0″✓
BromleyVT0.02″0.04″-0.02″✓
Mount SnowVT0.01″0.04″-0.03″✓
OkemoVT0.04″0.03″+0.01″✓
Magic MountainVT0.01″0.02″-0.01″✓
GunstockNH—0.01″-0.01″✓
LoonNH0.01″0.01″0.0″✓
SaddlebackME0.01″0.01″0.0″✓
SugarloafME0.01″0.01″0.0″✓
Sunday RiverME0.01″0.01″0.0″✓
AttitashNH0.01″—+0.01″✓
Berkshire EastMA0.01″—+0.01″✓
Black MountainNH0.01″—+0.01″✓
CranmoreNH——0.0″✓
CrotchedNH0.02″—+0.02″✓
Mount SunapeeNH——0.0″✓
Pats PeakNH——0.0″✓
RaggedNH——0.0″✓
WachusettMA0.01″—+0.01″✓
Waterville ValleyNH0.01″—+0.01″✓

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.