Clarion River At Johnsonburg
Clarion River · Northeast · USGS gage 03028500
Trout (marginal) (summer mean 17.6°C — trout, warm in summer).
Water
59°F
Flow
724 cfs
Air
49°F
Sky
0%
Pressure
30.19 in
Wind
3 mph
Predicted hatches · 2026-09-15
PredictedSlate Drake / IsonychiaIsonychia spp.0.53
Predicted by conditions; no reports yet. water 15.1°C (59°F) is warming toward the prime band (16-21°C); peak season; 8 days sustained ≥14°C; watch afternoon/evening; nymphs crawl to shore to emerge.
flies: Isonychia #10-12, Slate Drake, Leadwing Coachman
PredictedSpotted / Summer CaddisHydropsyche spp.0.48
Predicted by conditions; no reports yet. water 15.1°C (59°F) sits in 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
PredictedHopper / TerrestrialsAcrididae (grasshoppers)0.18
water 15.1°C (59°F) is warming toward the prime band (17-24°C); shoulder of the season; 8 days sustained ≥14°C; watch warm, breezy afternoons.
flies: Morrish Hopper #8-12, Chubby Chernobyl, Dave's Hopper
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.