Q.Freshwater Trout & Hatches
What is a Blue Winged Olive hatch?
A.
Blue Winged Olive (BWO) is a common name for several Baetis mayfly species that hatch in cool, overcast conditions throughout much of the year. BWO hatches occur in spring (March-May) and fall (September-November) on most Eastern and Western trout streams. They're size 16-20, slate-blue wings, olive bodies — an iconic small-fly hatch.
BWO hatches favor overcast, drizzling conditions over bright sun. Use #18-20 BWO dun and emerger patterns. Hatch calendar pages cover BWO timing.