Big Hole River At Maiden Rock near Divide
Big Hole River · Rockies · USGS gage 06025250
Trout (marginal) (summer mean 16.9°C — trout, warm in summer).
Water
53°F
Flow
253 cfs
Air
42°F
Sky
0%
Pressure
30.09 in
Wind
6 mph
Predicted hatches · 2026-09-15
PredictedBlue-Winged OliveBaetis spp.0.43
Predicted by conditions; no reports yet. water 11.4°C (53°F) is cooling past the prime band (6-11°C); shoulder of the season; 7 days sustained ≥4°C; watch midday, especially overcast afternoons.
flies: BWO Sparkle Dun #18-22, RS2, Pheasant Tail #18
PredictedMidgeChironomidae0.38
Predicted by conditions; no reports yet. water 11.4°C (53°F) is cooling past the prime band (1-10°C); shoulder of the season; 7 days sustained ≥0°C; watch midday, especially cold months.
flies: Zebra Midge #18-22, Griffith's Gnat, Disco Midge
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.