Bitterroot River Near Darby
Bitterroot River · Rockies · USGS gage 12344000
Coldwater (summer mean 15.2°C — prime coldwater).
Water
56°F
Flow
474 cfs
Air
49°F
Sky
11%
Pressure
29.96 in
Wind
2 mph
Predicted hatches · 2026-09-16
PredictedSpotted / Summer CaddisHydropsyche spp.0.40
Predicted by conditions; no reports yet. water 13.6°C (56°F) is warming toward the prime band (14-19°C); shoulder of the season; 8 days sustained ≥12°C; watch evening, last hour of light.
flies: Elk Hair Caddis #14-16, Iris Caddis, X-Caddis
PredictedMidgeChironomidae0.20
water 13.6°C (56°F) is cooling past the prime band (1-10°C); shoulder of the season; 8 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.