Madison River below Hebgen Lake
Madison River · Montana · USGS gage 06038500
Upper Madison just below Hebgen Dam — the 'between the lakes' water near West Yellowstone. Cold, prime coldwater.
Water
50°F
Flow
641 cfs
Air
33°F
Sky
100%
Pressure
29.94 in
Wind
6 mph
Predicted hatches · 2026-10-30
PredictedBlue-Winged OliveBaetis spp.1.00
Predicted by conditions; no reports yet. water 9.9°C (50°F) sits in the prime band (6-11°C); peak season; 7 days sustained ≥4°C; overcast skies favor it; watch midday, especially overcast afternoons.
flies: BWO Sparkle Dun #18-22, RS2, Pheasant Tail #18
PredictedMidgeChironomidae0.50
Predicted by conditions; no reports yet. water 9.9°C (50°F) sits in 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.