upslope

September 29, 2026 New England rain event — forecast vs. what fell

event hit rate 53% MAE 0.42″ 32 mountains scored

On September 29, 2026, 30 of 32 scored New England ski resorts recorded measurable rain, peaking at 1.19″ near Saddleback. upslope’s day-before forecasts verified at a 53% event hit rate with a mean absolute error of 0.42″ across 32 mountains. Ground truth: median of CoCoRaHS volunteer gauges near each resort (min 2 reporting).

Mountain by mountain

Resort Forecast Measured Error Call
SaddlebackME0.3″1.19″-0.89″✓
SugarloafME0.21″1.19″-0.98″✓
GunstockNH0.19″0.95″-0.76″✓
Pats PeakNH0.13″0.84″-0.71″✓
RaggedNH0.12″0.84″-0.72″✓
Mount SunapeeNH0.07″0.79″-0.72″✗
Waterville ValleyNH0.11″0.78″-0.67″✓
CrotchedNH0.1″0.74″-0.64″✓
Black MountainNH0.2″0.73″-0.53″✓
AttitashNH0.18″0.72″-0.54″✓
CranmoreNH0.19″0.72″-0.53″✓
Berkshire EastMA0.01″0.7″-0.69″✗
Sunday RiverME0.27″0.69″-0.42″✓
LoonNH0.11″0.6″-0.49″✓
WachusettMA0.06″0.52″-0.46″✗
CannonNH0.1″0.5″-0.4″✓
Magic MountainVT0.03″0.5″-0.47″✗
OkemoVT0.02″0.49″-0.47″✗
WildcatNH0.19″0.4″-0.21″✓
BromleyVT0.01″0.32″-0.31″✗
StrattonVT0.01″0.31″-0.3″✗
Bretton WoodsNH0.12″0.28″-0.16″✓
PicoVT0.03″0.22″-0.19″✗
KillingtonVT0.03″0.21″-0.18″✗
SugarbushVT0.02″0.21″-0.19″✗
Bolton ValleyVT—0.18″-0.18″✗
Mad River GlenVT0.01″0.18″-0.17″✗
Smugglers' NotchVT—0.18″-0.18″✗
Mount SnowVT0.02″0.17″-0.15″✗
StoweVT—0.17″-0.17″✗
BurkeVT0.03″0.09″-0.06″✓
Jay PeakVT—0.04″-0.04″✓

Forecast = upslope's last published NWS-based rain number the day before. ✓ = correctly called rain above/below 0.1″. Positive error = over-forecast.