Understanding the Blue Winged Olive Hatch
September fly fishing in Maine means one thing: Blue Winged Olives. These small but mighty mayflies from the Baetidae family are olive-bodied with transparent blue wings and range in size from #16 to #22.
One of the most beautiful aspects of the Blue Winged Olive (BWO) is their long hatch window. In Maine, BWOs can emerge anytime from early September through November. If you’re on the water in fall and see trout or salmon rising, chances are good a BWO will get the job done.
They may hatch throughout the day, but look for peak action between noon and 4 p.m., especially on cool, overcast, rainy, or even snowy afternoons.
The BWO Life Cycle & Matching the Hatch
Like other mayflies, BWOs progress through nymph, emerger, dun, and spinner stages. Knowing where fish are feeding in the water column is the key to success.
Fishing BWO Nymphs
Recommended flies:
- Pheasant Tail Nymph
- Rainbow Warrior
BWO nymphs are active swimmers but often get swept into the current. Fish them deep and heavy so your fly occasionally ticks bottom. Use added weight or bead-head patterns to keep them in the strike zone longer.
Fishing BWO Emergers
Go-to patterns:
- Baetis Soft Hackle
- BWO Wet Fly
Techniques:
- Lift & Swing Nymphs: Let your nymphs rise off the bottom at the end of the drift to mimic an emerging insect. Perfect when fish are feeding just under the surface.
- Swing a Wet Fly or Soft Hackle: Cast 45° downstream, let the current swing the fly, then pause at the hang-down before retrieving. Trout often crush it during this moment.
- Dry–Dropper Rig: Use a high-floating dry like a Chubby Chernobyl with a trailing RS2 or CDC Baetis about 18″ behind. The dry acts as both an attractor and an indicator for your small emerger.
Fishing BWO Duns (Dry Flies)
Effective patterns:
- Sparkle Dun
- Lexi’s Get’er Dun
- BWO Parachute
When BWOs emerge, they sit helplessly on the water until their wings dry. On damp fall days, this process takes longer — making them easy pickings for trout and salmon. September and October afternoons are some of the best times to catch Maine fish on dry flies.
Fishing BWO Spinners
Patterns to try:
- Spent Wing Olive
- Little BWO Spinner
- Olive Spinner CDC
In the evenings, look for mayflies hovering above the water with a weak, dipping flight pattern and rust-tinged bodies. These are spinners — old, spent insects that trout key in on during dusk feeding binges. Fish them dead-drifted with wings splayed flat on the water.
Fall Fly Fishing in Maine: Where to Go
As September winds down, many Maine rivers and streams begin to close, but the East Outlet of the Kennebec River is just heating up. This stretch is famous for its fall salmon run, when large, breeder-sized landlocked salmon display spawning colors and bright blue cheeks.
If you’re hunting in the Maine woods this fall, consider adding a “cast and blast” weekend — chase grouse or deer in the morning, then hit the river for salmon in the afternoon.
Final Thoughts & Book Your Trip
Fishing season in Maine doesn’t end in September. With Blue Winged Olives hatching well into November, there are still weeks of excellent fly fishing ahead. Whether you’re after brook trout sipping BWOs or salmon charging upriver, fall is one of the most rewarding times to be on the water.
Ready to experience it for yourself?
👉 Book your guided fly fishing trip with Horizon Line Adventures and fish the best fall hatches Maine has to offer. Visit www.horizonlineadventures.com to plan your adventure today.
