Jefferson River At Parsons Bdg near Silver Star
Jefferson River · Rockies · USGS gage 06027600
Trout (marginal) (summer mean 20.2°C — trout, warm in summer).
Water
55°F
Flow
252 cfs
Air
47°F
Sky
0%
Pressure
30.10 in
Wind
4 mph
Predicted hatches · 2026-09-15
PredictedMidgeChironomidae0.26
water 12.9°C (55°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
PredictedSpotted / Summer CaddisHydropsyche spp.0.23
water 12.9°C (55°F) is warming toward the prime band (14-19°C); shoulder of the season; 7 days sustained ≥12°C; watch evening, last hour of light.
flies: Elk Hair Caddis #14-16, Iris Caddis, X-Caddis
PredictedBlue-Winged OliveBaetis spp.0.18
water 12.9°C (55°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
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.