Free Resource · Updated 2026
The Big Wood River flows through the Wood River Valley past Ketchum and Hailey in central Idaho. It holds a mix of wild brown and rainbow trout in freestone water with good hatch diversity. PMD and Caddis hatches define the summer. Hopper fishing is excellent from late July through September.
Big Wood River Hatch Calendar — Quick Reference
The Big Wood drains from the Pioneer Mountains and flows south through the Sun Valley area. The most productive fishing is from Ketchum downstream through Hailey on the public access sections. The river runs freestone with riffles, pools, and undercut banks that hold good fish.
Brown trout are the dominant species in most of the river. Rainbows are more common in the colder upper sections. Both species respond well to dry flies during hatches and to hoppers in late summer. The fish average 10 to 14 inches with some browns in the 16 to 18 inch range in the heavier pools.
PMDs hatch through June and July and produce reliable dry fly fishing in the mornings. Caddis are the workhorse hatch from May through July. Golden Stones pass through in late May and June. Hoppers take over in August and can produce fish into late September.
See the full Idaho Fly Hatch Chart for hatch timing across all of Idaho's top trout streams.
Check Conditions Near Big Wood RiverWhat to Fish
PMDs hatch mid-morning on the Big Wood from June through August. The hatches are reliable and the fish respond well to a well-presented dun or emerger. Fish the flat water above riffles where trout hold and feed during the hatch. A Sparkle Dun or Comparadun in size 16 is a reliable choice.
Recommended: #16-18 Comparadun, Sparkle Dun
Hopper fishing on the Big Wood is some of the best in the Wood River Valley. August is the prime month. Fish a foam hopper close to the grassy banks where hoppers are most likely to fall in. Brown trout respond aggressively to a well-placed hopper in the late summer afternoon.
Recommended: #8-12 Dave's Hopper, Parachute Hopper
Caddis are one of the most consistent hatches on the Big Wood from May through July. The evening caddis hatches in June can be dense and bring fish up across the river. An Elk Hair Caddis fished in the surface film is a workhorse pattern. The X-Caddis is a good choice when fish are selective during heavy hatches.
Recommended: #14-18 Elk Hair Caddis, X-Caddis
FlyFishFinder combines hatch knowledge with live gauge alerts, Prime condition indicators, and real angler intel so you show up on the right day, not the wrong one.
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