Tuolumne River below Lagrange Dam near Lagrange
Tuolumne River · Sierra / West · USGS gage 11289650
Coldwater (summer mean 12.9°C — prime coldwater).
Water
54°F
Flow
104 cfs
Air
63°F
Sky
2%
Pressure
29.93 in
Wind
10 mph
Predicted hatches · 2026-06-20
PredictedGreen DrakeDrunella spp.1.00
Predicted by conditions; no reports yet. water 12.2°C (54°F) sits in the prime band (11-15°C); peak season; 8 days sustained ≥10°C; watch midday, often cloudy.
flies: Green Drake Parachute #10-12, Cripple, Hares Ear #10
PredictedMidgeChironomidae0.32
water 12.2°C (54°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 californica0.20
water 12.2°C (54°F) is warming toward the prime band (13-16°C); peak season; 8 days sustained ≥12°C; watch late morning through evening.
flies: Rogue Foam Salmonfly #4-6, Chubby Chernobyl, Pat's Rubber Legs
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.