Big Hole River
Big Hole Valley · Divide to Melrose
SW Montana, USA
Open live forecast →Target species: Brown, Rainbow, and Grayling.
Stream gauge: 06025500. Flow and water temperature update on every refresh.
Weekly AI Outlook as of 06/05/26
The Big Hole is firing on all cylinders at 2340 cfs with the salmonfly hatch actively progressing from Glen to Divide. Water temp hit 57.4°F — prime territory for continued stone emergence and PMD action. Sunrise Fly Shop confirms strong dry fly fishing from Melrose down to Brownes Bridge as flows drop and clarity improves. Focus canyon water above Melrose for peak stone concentrations, but don't sleep on the lower reaches where fish are keyed on dries. Saturday's cold front and rain could slow surface activity temporarily but should keep flows stable through the weekend.
- Flow: 2340 cfs and dropping — perfect salmonfly water with improving clarity as runoff stabilizes through the canyon reaches
- Hatches: Salmonflies active Glen to Divide, PMDs starting to show at 57.4°F water temp, with golden stones and caddis filling gaps
- Water Temp: 57.4°F — ideal for stone activity and PMD emergence, warm enough to keep fish looking up despite cooler air temps ahead
- Best Window: Midday through late afternoon for surface action, morning streamers before stones get going around 11am
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–July & Sept
The Big Hole River flows through one of Montana's most remote and undeveloped valleys — a broad, cottonwood-lined freestone river that produces exceptional fishing for brown trout, rainbow trout, and native Arctic grayling in the upper reaches. It is one of the last rivers in the lower 48 with a wild, self-sustaining population of Arctic grayling. The Big Hole's character varies dramatically — from technical spring-creek glides in the upper valley to tumbling canyon pocket water below Divide.
The Big Hole is home to one of the last wild Arctic grayling populations in the continental United States — the Upper Big Hole above Wisdom is their primary stronghold.
January Outlook
The Big Hole in January is a remote winter fishery. Cold and often frozen in the valley, but the canyon sections above Divide stay open. Midge fishing in the deep pools for the most dedicated anglers.
Productive Patterns
- Zebra Midge
- RS2
- Pheasant Tail
- Soft Hackle
Tips
The canyon above Divide is the most reliably ice-free section. Dress for sub-zero potential. Target the deepest runs and pools. A single small midge under an indicator is the go-to approach.
Water Notes
500–1,000 cfs. Valley sections may freeze. Canyon above Divide stays open most winters. Water 34–40°F.
February Outlook
February Big Hole starts to show life as days lengthen. The canyon sees increasing midge activity. A hint of Skwala nymph activity begins in the warmest sections by late February.
Productive Patterns
- Zebra Midge
- RS2
- Hare's Ear
- WD-40
Tips
Check the canyon stretch near Wisdom and Wise River. The Skwala hatch season is approaching — fish brown stonefly nymphs throughout February. Slow your drift significantly.
Water Notes
500–900 cfs. Stabilizing as winter progresses. Canyon sections 36–44°F.
March Outlook
March brings the first Skwala action on the Big Hole. The canyon above Melrose is often the first section to produce Skwala dries in the state. A signal that spring is coming to this remarkable river.
Productive Patterns
- Skwala Stone #8
- Hare's Ear
- Sparkle Dun #18
- Brown Rubber Leg
Tips
Early March — Skwala nymphs throughout. Mid-month, watch for the first dry fly Skwala action on warm afternoon days when air temps reach 50°F. The canyon above Melrose is the bellwether section.
Water Notes
600–1,500 cfs. Snowmelt begins building later in the month. Water 40–50°F in early March.
April Outlook
The Skwala stonefly hatch here is legendary — this is considered home water for Skwalas in the West.
Productive Patterns
- Skwala Stone #8
- Brown Rubber Leg
- Hare's Ear
- Sparkle Dun
Tips
Skwala hatch begins mid-April. Fish banks with a Skwala dry early morning when adults crawl on rocks. Nymphs work through the day. Lower canyon above Melrose is best.
Water Notes
800–2,000 cfs in April — runoff transition. Check conditions; early April before snowmelt is often best.
May Outlook
Multiple overlapping hatches as runoff subsides — PMDs, Golden Stones, and Caddis all appear within weeks.
Productive Patterns
- PMD
- Golden Stone
- Stimulator
- Elk Hair Caddis
Tips
Watch the USGS gauge and plan when flows drop below 1,500 cfs and clarity returns. Canyon above Divide clears first.
Water Notes
Flows dropping from peak — target 1,000–2,500 cfs range. Late May can produce exceptional fishing.
June Outlook
Prime time. The Salmonfly hatch moves through the canyon in early June — a spectacle rarely matched in freshwater fishing.
Productive Patterns
- Salmonfly #4
- Stimulator
- Golden Stone
- PMD
Tips
The Salmonfly on the Big Hole is less predictable than the Madison but extraordinary when you hit it. Monitor conditions and be flexible. Canyon above Melrose holds best concentrations.
Water Notes
1,500–3,500 cfs early June dropping to 800–1,500 cfs late June. One of Montana's finest June fisheries.
July Outlook
Prime summer on the Big Hole. Salmonfly winding down, caddis and PMD hatches dominating. Hoppers starting on warm afternoons. Arctic Grayling active in upper valley sections near Wisdom.
Productive Patterns
- Elk Hair Caddis #14
- PMD Sparkle Dun #16
- Chubby Chernobyl #10
- Pat's Rubber Legs #8
Tips
Fish mornings for PMDs, afternoons for hoppers. Watch water temps — if the gauge reads above 67°F at Melrose, move to the cooler upper sections near Wisdom. Grayling in the upper Big Hole all day.
Water Notes
Flows dropping from June peak. Ideal conditions 800–1500 cfs at Melrose gauge.
August Outlook
Peak hopper-dropper season on the Big Hole. PMDs continue mornings. Caddis evenings. Trico spinner falls at dawn in lower sections near Twin Bridges. Monitor temps — voluntary closures possible in drought years.
Productive Patterns
- Dave's Hopper #10
- PMD Parachute #16
- Trico Spinner #22
- Elk Hair Caddis #14
Tips
Early morning Trico spinner falls from 6–9 AM. Hopper fishing best 11 AM to 3 PM on warm, breezy days. Rest the river 2–5 PM if temps spike. Grayling in upper river sections stay active all day.
Water Notes
Lowest flows of year. Watch for FWP hoot-owl restrictions — fishing prohibited 2 PM to midnight when temps are critical.
September Outlook
Fall transition on the Big Hole. Cooler mornings bring BWOs returning on overcast days. Browns becoming aggressive pre-spawn. Hopper fishing continues warm afternoons. Dramatically reduced pressure compared to summer.
Productive Patterns
- BWO Sparkle Dun #18
- Dave's Hopper #10
- Pheasant Tail #16
- Elk Hair Caddis #14
Tips
September is arguably the Big Hole's finest month — comfortable temps, active fish, minimal crowds. Fish the Divide to Melrose float for the best fall experience. BWOs on overcast afternoons; hoppers on sunny days.
Water Notes
Flows stabilizing 500–1000 cfs. Water temps ideal at 52–62°F.
October Outlook
Late fall on the Big Hole. BWO hatches on grey afternoons remain productive. Large browns staging for spawn — streamer fishing in deeper runs is excellent. Season winding toward November closure.
Productive Patterns
- Woolly Bugger #6
- BWO Parachute #18
- Pheasant Tail #16
- Sculpzilla #4
Tips
Streamers early morning and late evening for trophy browns. BWO dry fly fishing midday on overcast days. Check FWP for section-specific closure dates. Dress warm — Big Hole Valley frosts come early.
Water Notes
Cooling rapidly. Water temps 45–55°F. Flows 400–800 cfs.
November Outlook
Late season on the Big Hole as brown trout spawning concludes. Midges and Baetis nymphs produce fish on mild days. The canyon sections fish better than the exposed valley in November cold.
Productive Patterns
- Zebra Midge
- Juju Baetis
- Pheasant Tail
- RS2
Tips
Focus the canyon above Divide for November fishing. Midday warming window is short — fish noon–2pm. Respect any remaining spawning redds. The season is winding down but fish are still active.
Water Notes
400–800 cfs. Cold and stable. Canyon sections 38–46°F.
December Outlook
December on the Big Hole is quiet and cold. The canyon can fish on mild stretches. Midge fishing in the deep pools for those who know the river and the right sections to target in winter.
Productive Patterns
- Zebra Midge
- RS2
- Mercury Midge
- WD-40
Tips
The Big Hole in December requires local knowledge. Fish the canyon above Divide in deep pools during the midday window. Don't be surprised if you have the water entirely to yourself.
Water Notes
400–700 cfs. Cold — valley sections may freeze. Canyon pools stay open. Water 34–40°F.
Hatch Calendar
| Insect | Peak | Active | Size | Productive Patterns |
|---|---|---|---|---|
| Skwala Stonefly Skwala americana |
Apr | Mar, Apr | #8–10 |
|
| Blue Winged Olive Baetis tricaudatus |
Apr, Oct | Mar, Apr, May, Sep, Oct, Nov | #18–22 |
|
| Salmonfly Pteronarcys californica |
Jun | Jun, Jul | #4–8 |
|
| Golden Stonefly Hesperoperla pacifica |
Jul | Jun, Jul | #8–12 |
|
| Pale Morning Dun Ephemerella inermis |
Jul | Jun, Jul, Aug | #14–16 |
|
| Caddis Hydropsyche / Brachycentrus spp. |
Jul, Aug | Jun, Jul, Aug, Sep | #14–16 |
|
| Yellow Sally Isoperla / Chloroperlidae |
Jul | Jun, Jul, Aug | #12–16 |
|
| Trico Tricorythodes spp. |
Aug | Aug, Sep | #20–24 |
|
| Hoppers Acrididae / Tettigoniidae |
Aug | Jul, Aug, Sep | #8–12 |
|
Access & Approach
Wisdom, Divide, and Twin Bridges are the main access towns. Numerous Montana Department of Fish, Wildlife & Parks fishing access sites throughout. Float and wade options available. Hatch matching demands attention — consult local shops in Dillon or Twin Bridges.
Nearby Fly Shops
- Sunrise Fly Shop
- Backcountry Angler
Regulations & License
Fishing in Montana requires a current license. Always verify season dates, bag limits, and any special-regulation waters before you fish.
Montana fishing regulations & license →
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About Current
Big Hole 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.
Big Hole River is one of 245 hand-curated waters in Current. The app and web forecast also generate AI outlooks for any unlisted river, lake, or saltwater flat anywhere in the world — drop a pin or paste a name and Current produces a fresh seasonal outlook with weather, flow context, and recommended techniques.
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