Au Sable River Near Red Oak
Au Sable River · Driftless / Midwest · USGS gage 04136000
Trout (marginal) (summer mean 18.7°C — trout, warm in summer).
Water
58°F
Flow
797 cfs
Air
57°F
Sky
100%
Pressure
30.03 in
Wind
11 mph
Predicted hatches · 2026-09-15
PredictedSpotted / Summer CaddisHydropsyche spp.0.50
Predicted by conditions; no reports yet. water 14.2°C (58°F) sits in the prime band (14-19°C); shoulder of the season; 5 days sustained ≥12°C; watch evening, last hour of light.
flies: Elk Hair Caddis #14-16, Iris Caddis, X-Caddis
PredictedMidgeChironomidae0.15
water 14.2°C (58°F) is cooling past the prime band (1-10°C); shoulder of the season; 5 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.