When does the Blue Winged Olive hatch?

The Blue Winged Olive typically runs for 6 weeks. Peak emergence occurs in the afternoon.

What water temperature triggers the Blue Winged Olive hatch?

The Blue Winged Olive hatches when water temperature is between 45°F and 55°F, with peak activity around 50°F.

Parachute BWO #18-20, CDC Comparadun #18-20, Pheasant Tail Nymph #18, RS2 #20.

Hatch profile

Baetis spp.

MayflyAfternoon

Water-temperature trigger

30°F45–55°Fpeak 50°F80°F

Top fly patterns

Most reliable Eastern hatch. Two emergences — spring (March-April) and fall (September-October). Best on overcast, drizzly days.

Best rivers

Other rivers with Blue Winged Olive activity

Bield Fish watches USGS water-temp gauges for your home water and pings you when conditions hit the 45–55°F trigger window.