St. Louis Creek Near Fraser, Co.
St. Louis Creek · Rockies · USGS gage 09026500
Coldwater (summer mean 10.4°C — prime coldwater).
Water
55°F
Flow
14 cfs
Air
60°F
Sky
0%
Pressure
29.88 in
Wind
3 mph
Predicted hatches · 2026-07-31
PredictedPale Morning DunEphemerella spp.0.50
Predicted by conditions; no reports yet. water 12.5°C (55°F) is warming toward the prime band (13-18°C); peak season; 8 days sustained ≥12°C; watch late morning to early afternoon.
flies: PMD Comparadun #16-18, Sparkle Dun, Pheasant Tail #16
PredictedGreen DrakeDrunella spp.0.50
Predicted by conditions; no reports yet. water 12.5°C (55°F) sits in the prime band (11-15°C); shoulder of the season; 8 days sustained ≥10°C; watch midday, often cloudy.
flies: Green Drake Parachute #10-12, Cripple, Hares Ear #10
PredictedMidgeChironomidae0.29
water 12.5°C (55°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
PredictedSalmonflyPteronarcys californica0.25
water 12.5°C (55°F) is warming toward the prime band (13-16°C); shoulder of the season; 8 days sustained ≥12°C; watch late morning through evening.
flies: Rogue Foam Salmonfly #4-6, Chubby Chernobyl, Pat's Rubber Legs
PredictedSpotted / Summer CaddisHydropsyche spp.0.25
water 12.5°C (55°F) is warming toward the prime band (14-19°C); peak season; 8 days sustained ≥12°C; watch evening, last hour of light.
flies: Elk Hair Caddis #14-16, Iris Caddis, X-Caddis
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.