Big Wood River
Ketchum to Bellevue
S Idaho, USA
Open live forecast →Target species: Rainbow and Brown.
Stream gauge: 13139510. Flow and water temperature update on every refresh.
Weekly AI Outlook as of 06/05/26
The Big Wood is running 967 cfs — well above ideal wading levels but fishable with careful approach. Peak PMD season is here with shop reports confirming strong midday emergers and spinnerfall action. Water temps in the mid-50s are triggering consistent hatches. Focus pocket water and slower runs where fish can hold without fighting the current. Evening caddis opportunities remain strong despite higher flows.
- Flow: 967 cfs — nearly double ideal levels but manageable. Stick to bank water and deeper pools where fish aren't fighting current.
- Hatches: PMDs peaking with strong midday emergence 11am-2pm. Size #16-18 Comparaduns and Sparkle Duns. Evening caddis still active.
- Water Temp: Mid-50s — perfect for PMD emergence and keeping fish active through midday. Cool enough to prevent heat stress.
- Best Window: 11am-2pm for PMD dry fly action, then evening caddis rise as temps cool. Avoid early morning when flows feel heaviest.
Generated weekly from live USGS gauge readings, weather forecasts, and recent fly shop reports. Updates Friday mornings.
About this Water
- Freestone
- Best months: May–Oct, peak June (salmonfly) & Aug
The Big Wood River in central Idaho runs through the Wood River Valley near Sun Valley — a freestone river supporting wild rainbow and brown trout in classic high-desert mountain country. The Silver Creek Preserve area (separate listing) is the famous spring-creek tributary. The Big Wood mainstream offers more accessible freestone fishing throughout the Hailey-Bellevue corridor. Hatches are reliable: salmonflies in early summer, caddis through July, and the famous Trico hatch through August mornings.
The Big Wood Trico hatch through August produces some of the most demanding small-fly fishing in the West — broad, slow runs through the valley meadow stretches with fish rising to size 22 spinners in dead-drift presentations.
January Outlook
The Big Wood near Ketchum is cold and largely frozen in January. A small amount of midge activity occurs in the warmest deep pools near town. Not a practical fishing month but the Ketchum area ski season is in full swing.
Productive Patterns
- Zebra Midge
- RS2
Tips
The Big Wood in January is not worth a special trip. Local anglers occasionally midge fish the pools below Ketchum on mild afternoons. Better to plan the spring season.
Water Notes
100–300 cfs. Partially iced. Water 32–38°F. Very cold.
February Outlook
February sees the Big Wood beginning to wake up. Midging in the canyon pools near Ketchum on the warmest days. A hint of spring is coming — Skwala nymphs begin appearing in the gravels late in the month.
Productive Patterns
- Zebra Midge
- RS2
- Hare's Ear
Tips
Late February midge fishing is possible near Ketchum on warm days. The ski season is winding down and spring fishing preparation begins at Sturtevants and other local shops.
Water Notes
150–350 cfs. Warming slightly 34–42°F. Canyon sections stay open.
March Outlook
March brings the first serious Baetis and Skwala activity to the Big Wood. One of the first spring rivers to produce dry fly fishing in Idaho. Early March is midge-only; late March can produce brief Skwala action.
Productive Patterns
- Sparkle Dun #18
- RS2
- Skwala Stone
- Zebra Midge
Tips
The Big Wood responds quickly to spring warmth. Canyon sections near the Bellevue area produce the first Skwala action. Call Ketchum shops for current hatch reports.
Water Notes
200–500 cfs building. Water 40–50°F. Spring fishing approaching quickly.
April Outlook
April runoff arrives on the Big Wood. The canyon runs off quickly — check the Bellevue gauge. Late April can provide excellent caddis and early PMD fishing as flows moderate.
Productive Patterns
- Elk Hair Caddis
- Stimulator
- PMD (late April)
- Hare's Ear
Tips
The Big Wood clears faster than most Idaho rivers. Target late April when flows drop below 400 cfs and clarity returns. A good option before the South Fork Snake season opens May 1.
Water Notes
400–1,500 cfs and dropping by month end. Variable clarity. Late April can be excellent.
May Outlook
The Big Wood near Ketchum fishes well as runoff subsides. PMDs and Caddis bring trout to the surface in the quality sections.
Productive Patterns
- PMD
- Elk Hair Caddis
- Hare's Ear
- Stimulator
Tips
The sections above and below Hailey fish best as flows drop below 400 cfs. The Bellevue Canyon section clears fastest. A good alternative when Silver Creek is too low-pressure intimidating.
Water Notes
Flows drop from 500–800 cfs peak to 200–400 cfs by late May. Clear and cold 48–56°F.
June Outlook
Excellent late-spring dry fly fishing with Golden Stones, PMDs, and Caddis. The Big Wood fishes like a compressed version of Montana's best rivers.
Productive Patterns
- Golden Stone
- PMD
- Elk Hair Caddis
- Stimulator #12
Tips
Wade the canyon sections carefully — the Big Wood has character and the pocket water holds fish. Evening caddis fishing in the Ketchum area is a local tradition.
Water Notes
200–500 cfs ideally. Clear and cold 52–58°F. Good wading access from the bike path system.
July Outlook
Hopper-dropper fishing and evening caddis action. The Big Wood's proximity to Sun Valley makes it heavily visited but the fish are plentiful.
Productive Patterns
- Hopper-Dropper
- Elk Hair Caddis
- PMD Cripple
- Beadhead Nymph
Tips
Fish the sections with less access — the bike path brings anglers to the easy spots. Walk to the water between town and the highway for less pressure.
Water Notes
150–350 cfs. Water 60–66°F. The Big Wood is small — intimate fishing experience.
August Outlook
Hopper season with cooling evening sessions. The Big Wood can fish surprisingly well in August if water temps stay manageable.
Productive Patterns
- Hopper
- Parachute Ant
- Elk Hair Caddis
- Bead Head Nymph
Tips
Fish the evening window when temps cool. The deeper pools hold fish through the warmest days. Small nymph dropper on a hopper is the go-to rig.
Water Notes
100–250 cfs. Water can warm to 66–70°F midday. Fish early morning and evening.
September Outlook
Fall BWO fishing on a beautiful mountain stream. The Big Wood in September is a wonderful local fishery.
Productive Patterns
- Blue Winged Olive
- Elk Hair Caddis
- Mahogany Dun
- Soft Hackle
Tips
The autumn BWO hatch produces excellent fishing from 1–4pm on overcast afternoons. Fish the flatter sections for rising fish.
Water Notes
100–200 cfs. Clear and cooling 50–58°F. Good wading throughout.
October Outlook
Fall BWO and Mahogany Dun hatches on the Big Wood. Brown trout are aggressive before spawning. The Ketchum area has spectacular fall color. An excellent and overlooked October river.
Productive Patterns
- Blue Winged Olive
- Mahogany Dun
- Streamer
- Elk Hair Caddis
Tips
October on the Big Wood with an overcast afternoon BWO hatch can be exceptional. The sections below Hailey have the most productive fall fishing. Very little October pressure.
Water Notes
100–250 cfs. Clear and cool 44–52°F. Prime fall conditions. Ketchum cottonwoods are spectacular.
November Outlook
November closes out the Big Wood season. Cold temperatures limit fishing to mild afternoons. Midge activity in the deeper pools near Ketchum.
Productive Patterns
- Zebra Midge
- RS2
- Juju Baetis
- Pheasant Tail
Tips
November can produce good midge fishing on warm afternoons in the canyon pools. The season is winding down — fish aggressively when conditions cooperate.
Water Notes
100–200 cfs. Cold 36–44°F. Canyon sections stay open. Snow possible at any time.
December Outlook
December closes the Big Wood for winter. The canyon near Ketchum can fish on the mildest days but conditions are unreliable. A quiet end to the season.
Productive Patterns
- Zebra Midge
- RS2
Tips
The Big Wood in December is for locals only. Fish the warmest pools in the canyon near town on mild afternoons. Not worth a special trip — plan the spring season instead.
Water Notes
75–175 cfs. Cold 32–38°F. Partially iced. Off season.
Hatch Calendar
| Insect | Peak | Active | Size | Productive Patterns |
|---|---|---|---|---|
| Blue Winged Olive Baetis spp. |
Apr, Oct | Apr, May, Sep, Oct, Nov | #18–22 |
|
| Pale Morning Dun Ephemerella infrequens |
Jun, Jul | Jun, Jul, Aug | #16–18 |
|
Access & Approach
Sun Valley, Ketchum, and Hailey, ID are the main bases. Public access at multiple state-managed sites. Idaho fishing license required.
Nearby Fly Shops
- Silver Creek Outfitters
- Lost River Outfitters
Regulations & License
Fishing in Idaho requires a current license. Always verify season dates, bag limits, and any special-regulation waters before you fish.
Idaho fishing regulations & license →
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About Current
Big Wood River conditions on Current combine real-time flow data (USGS, WSC, CDEC, CEHQ), weather, tide predictions, hatch probabilities calibrated to this specific water, and recent fly shop reports from the area.
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