upslope

September 28, 2026 New England rain event — forecast vs. what fell

event hit rate 94% MAE 0.21″ 32 mountains scored

On September 28, 2026, 31 of 32 scored New England ski resorts recorded measurable rain, peaking at 2.0″ near Wachusett. upslope’s day-before forecasts verified at a 94% event hit rate with a mean absolute error of 0.21″ across 32 mountains. Ground truth: median of CoCoRaHS volunteer gauges near each resort (min 2 reporting).

Mountain by mountain

Resort Forecast Measured Error Call
WachusettMA0.84″2.0″-1.16″✓
Waterville ValleyNH0.47″0.9″-0.43″✓
SaddlebackME0.35″0.76″-0.41″✓
SugarloafME0.55″0.76″-0.21″✓
AttitashNH0.56″0.72″-0.16″✓
CranmoreNH0.69″0.72″-0.03″✓
Berkshire EastMA0.8″0.71″+0.09″✓
Black MountainNH0.66″0.61″+0.05″✓
GunstockNH0.97″0.54″+0.43″✓
WildcatNH0.5″0.53″-0.03″✓
Pats PeakNH0.91″0.48″+0.43″✓
Sunday RiverME0.51″0.46″+0.05″✓
CrotchedNH0.78″0.42″+0.36″✓
RaggedNH0.91″0.4″+0.51″✓
LoonNH0.21″0.39″-0.18″✓
Mount SunapeeNH0.73″0.38″+0.35″✓
Magic MountainVT0.56″0.35″+0.21″✓
StrattonVT0.6″0.35″+0.25″✓
Bretton WoodsNH0.21″0.34″-0.13″✓
BromleyVT0.47″0.34″+0.13″✓
PicoVT0.38″0.33″+0.05″✓
SugarbushVT0.37″0.33″+0.04″✓
OkemoVT0.44″0.31″+0.13″✓
Mount SnowVT0.61″0.29″+0.32″✓
Mad River GlenVT0.3″0.27″+0.03″✓
KillingtonVT0.43″0.26″+0.17″✓
Bolton ValleyVT0.13″0.24″-0.11″✓
CannonNH0.22″0.24″-0.02″✓
BurkeVT0.21″0.13″+0.08″✓
StoweVT0.09″0.12″-0.03″✗
Smugglers' NotchVT0.08″0.11″-0.03″✗
Jay PeakVT0.05″0.03″+0.02″✓

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