San Juan River Near Archuleta
San Juan River · Rockies · USGS gage 09355500
Coldwater (summer mean 10.2°C — prime coldwater).
Water
55°F
Flow
509 cfs
Air
87°F
Sky
6%
Predicted hatches · 2026-06-16
PredictedGreen DrakeDrunella spp.0.60
Predicted by conditions; no reports yet. water 12.9°C (55°F) sits in the prime band (11-15°C); peak season; watch midday, often cloudy.
flies: Green Drake Parachute #10-12, Cripple, Hares Ear #10
PredictedSalmonflyPteronarcys californica0.54
Predicted by conditions; no reports yet. water 12.9°C (55°F) is warming toward the prime band (13-16°C); peak season; watch late morning through evening.
flies: Rogue Foam Salmonfly #4-6, Chubby Chernobyl, Pat's Rubber Legs
PredictedPale Morning DunEphemerella spp.0.27
water 12.9°C (55°F) is warming toward the prime band (13-18°C); shoulder of the season; watch late morning to early afternoon.
flies: PMD Comparadun #16-18, Sparkle Dun, Pheasant Tail #16
PredictedEastern Green DrakeEphemera guttulata0.27
water 12.9°C (55°F) is warming toward the prime band (14-18°C); peak season; watch evening; the spinner (Coffin Fly) falls at dusk.
flies: Green Drake #8-10, Coffin Fly Spinner, Drake Emerger
PredictedMidgeChironomidae0.26
water 12.9°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
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.