Clark Fork River
Missoula to Alberton
W Montana, USA
Open live forecast →Target species: Brown, Rainbow, and Bull Trout.
Stream gauge: 12340500. Flow and water temperature update on every refresh.
Weekly AI Outlook as of 06/05/26
At 8160 cfs and 54.9°F, the Clark Fork is right at the sweet spot where runoff fishing transitions to quality summer conditions. Grizzly Hackle reports caddis still active with PMDs and yellow sallies showing up in town — classic early June timing. Nymphing remains most consistent with stonefly patterns, worms, and attractor nymphs leading the way. Float fishing will be key given the flow, focus on deeper slots and soft water behind structure.
- Flow: 8160 cfs — high but fishable, within prime June range. River should be clearing progressively from upstream sections.
- Hatches: Caddis emergence continuing, PMDs and yellow sallies appearing. Water temp crossing key mayfly thresholds.
- Water Temp: 54.9°F — ideal for PMD emergence and continued caddis activity. Salmonfly window approaching.
- Best Window: Midday for mayfly activity, evenings for caddis. Nymphing productive throughout day in deeper runs.
Generated weekly from live USGS gauge readings, weather forecasts, and recent fly shop reports. Updates Friday mornings.
About this Water
- Freestone
- Best months: Apr–Oct, peak June (skwala/salmonfly) & Sept
The Clark Fork is Montana's longest river and one of the West's great recovery stories — once heavily impacted by upstream mining, now a productive freestone trout fishery through its middle and lower reaches. The river runs west from Butte through Missoula and on to the Idaho border, picking up the Bitterroot, Blackfoot, and Flathead along the way. Each reach has its own character: the upper river above Drummond is intimate and wadeable; the Missoula stretch is broad with strong drift-boat water; the lower river below the Flathead confluence is big-water freestone fishing for browns and rainbows.
The Clark Fork's recovery from a century of upstream mining contamination — including the largest Superfund cleanup in US history — has produced one of the most successful river-restoration stories in North America.
January Outlook
The Clark Fork near Missoula stays open in winter and offers productive midge fishing on mild days. The river's large volume moderates temperatures relative to smaller streams. A good option for winter anglers near Missoula.
Productive Patterns
- Zebra Midge
- RS2
- WD-40
- Juju Baetis
Tips
Fish the Missoula section between the university and the I-90 bridge in January. Target slow inside bends on a two-midge indicator rig. The river's size means fish are spread — look for concentrations in slow, deep tailouts.
Water Notes
4,000–8,000 cfs. River rarely freezes near Missoula. Water 34–40°F. Cold but fishable.
February Outlook
February midging on the Clark Fork. As days lengthen, afternoon BWO activity begins on the warmest days. The river offers accessible winter fishing in the Missoula corridor.
Productive Patterns
- Zebra Midge
- RS2
- Vis-A-Dun #20
- Soft Hackle
Tips
Fish the sections with slower current where fish can hold without burning energy in cold water. A warm February afternoon can produce BWO activity — have a dry-dropper rig ready.
Water Notes
4,000–7,000 cfs. Variable winter flows. Water 36–44°F. Missoula city reach stays open most winters.
March Outlook
March midging with increasing BWO activity. The Clark Fork begins its pre-runoff fishing season. The section near Missoula and below Milltown provides consistent early season access.
Productive Patterns
- Sparkle Dun #18
- Zebra Midge
- RS2
- Soft Hackle Emerger
Tips
March BWO hatches are building — overcast afternoons 11am–2pm are prime. The river will blow out with snowmelt before long — fish whenever you can in March.
Water Notes
5,000–10,000 cfs building toward runoff. Water 40–50°F. Fish before flows peak in mid-to-late April.
April Outlook
April runoff makes the Clark Fork challenging but the first half of the month can offer productive fishing before flows peak. Fish the inside seams and side channels with streamers.
Productive Patterns
- Streamer
- Jig Nymph
- Elk Hair Caddis
- Woolly Bugger
Tips
Large streamers and jig nymphs are the go-to approach in high, colored water. Eddy lines and inside bends are the most productive. Check the Bandmann Flats gauge daily.
Water Notes
8,000–18,000 cfs at peak. Very turbid at maximum runoff. Target early April before flows peak.
May Outlook
The Clark Fork is typically in full runoff through most of May. The Milltown section clears first. Late May can provide the first fishable conditions as flows drop and clarity returns.
Productive Patterns
- Elk Hair Caddis
- Streamer
- PMD Sparkle Dun
- Stimulator
Tips
Monitor the Bandmann Flats gauge — target when CFS drops below 10,000 and clarity returns. The section below Milltown reservoir (now removed) clears faster. Late May caddis can be explosive.
Water Notes
Flows dropping from peak but still high. Target late May when below 12,000 cfs and visibility allows.
June Outlook
Clark Fork clears in June and fishing can be excellent with PMD, Caddis, and Golden Stone activity.
Productive Patterns
- PMD Sparkle Dun
- Elk Hair Caddis
- Golden Stone
- Stimulator
Tips
Section between Missoula and Milltown Reservoir fishes well. Float fishing more effective than wading given the river's size. Evening caddis hatch can be prolific.
Water Notes
8,000–18,000 cfs in June — still high but fishable. River clears progressively from upstream.
July Outlook
Prime condition. Hopper-dropper fishing along the banks is excellent and the evening caddis hatch is one of the best in the region.
Productive Patterns
- Hopper-Dropper
- Elk Hair Caddis
- PMD
- Copper John
Tips
Float the Clark Fork for hopper fishing along gravel bar banks. Evening caddis from 7–9pm is exceptional.
Water Notes
5,000–10,000 cfs. Water 60–66°F. Float fishing strongly preferred over wading.
August Outlook
Consistent hopper fishing and Trico spinner falls. The river's size supports large populations of brown and rainbow trout.
Productive Patterns
- Hopper
- Trico Spinner
- Elk Hair Caddis
- Parachute Ant
Tips
Early morning Trico spinner falls in slower sections below Missoula. Afternoon hopper fishing along grassy banks is reliable. Float the river for efficiency.
Water Notes
4,000–7,000 cfs. Water 62–68°F — manageable. Large water maintains good temperature.
September Outlook
Excellent. BWO hatches return, pressure drops after summer, and large brown trout become very active ahead of spawning.
Productive Patterns
- Blue Winged Olive
- Mahogany Dun
- Streamer
- Hopper
Tips
Float the Clark Fork for best September access. River has numerous public fishing easements but they can be hard to find. A guide or boat significantly improves the experience.
Water Notes
3,000–5,500 cfs. Clearing and cooling. Water 54–62°F.
October Outlook
Excellent fall fishing on the Clark Fork. Large brown trout are very aggressive before spawning. BWO hatches on overcast afternoons. Float fishing from Missoula downstream is outstanding.
Productive Patterns
- Articulated Streamer
- Blue Winged Olive
- Mahogany Dun
- Hopper (early October)
Tips
October is the Clark Fork's finest month for large fish. Float from the Milltown confluence downstream. Pre-spawn browns attack large streamers along undercut banks and log jams.
Water Notes
3,500–6,000 cfs. Clear and cooling. Water 44–54°F. Best streamer conditions of the year.
November Outlook
November midge fishing on the Clark Fork. The river's large volume stays open through winter. Brown trout spawning concludes. Less dramatic than October but productive for dedicated anglers near Missoula.
Productive Patterns
- Zebra Midge
- RS2
- Juju Baetis
- Pheasant Tail
Tips
Fish the Missoula city reach between the university and I-90 bridge. Target slow inside bends noon–2pm. The Clark Fork near Missoula is one of the most accessible winter fisheries in western Montana.
Water Notes
4,000–7,000 cfs. Cold 38–46°F. Missoula reach stays open through winter.
December Outlook
Winter midge fishing on the Clark Fork near Missoula. Accessible from the riverfront trail system. The river's size moderates winter temperatures relative to smaller streams.
Productive Patterns
- Zebra Midge
- RS2
- Mercury Midge
- WD-40
Tips
The Clark Fork running through downtown Missoula is accessible year-round. Noon–2pm midge window. The university bridge area has reliable access even in winter.
Water Notes
3,500–6,500 cfs. Cold 34–42°F. Main channel stays open year-round near Missoula.
Hatch Calendar
| Insect | Peak | Active | Size | Productive Patterns |
|---|---|---|---|---|
| Skwala Stonefly Skwala americana |
Mar, Apr | Mar, Apr | #8–10 |
|
| Blue Winged Olive Baetis tricaudatus |
Apr, Oct | Mar, Apr, May, Sep, Oct, Nov | #18–22 |
|
| March Brown Rhithrogena morrisoni |
Apr, May | Apr, May | #12–16 |
|
| Gray Drake Siphlonurus quebecensis |
May | May, Jun | #10–12 |
|
| Salmonfly Pteronarcys californica |
Jun | May, Jun, Jul | #4–8 |
|
| Caddis Hydropsyche / Brachycentrus spp. |
Jul, Aug | May, Jun, Jul, Aug, Sep | #14–18 |
|
| Pale Morning Dun Ephemerella inermis |
Jul | Jun, Jul, Aug | #16–18 |
|
| Hoppers Acrididae / Tettigoniidae |
Aug | Jul, Aug, Sep | #8–12 |
|
Access & Approach
Missoula is the primary base. Numerous fishing access sites along I-90 and Highway 200. Float trips dominate the productive water. Montana fishing license required.
Nearby Fly Shops
- Grizzly Hackle
- Missoulian 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
Clark Fork 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.
Clark Fork 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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