Freestone · Mixed · Montana

Clark Fork

Wide view of a gravel road crossing the Clark Fork River on a bridge, with a road sign reading Clark Fork River, cottonwoods and mountains in the background

The Clark Fork is a river with a hard past — the upper reaches carried a century of mining poison out of Butte, and what you fish today is the product of an enormous cleanup.

Poor · Rainbow Trout
Parachute Adams · 12-18
Poorlive now
Not the day for it
River steady at a fishable height. Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
90% confidence
What moved it
  • Level0.69 mLast reading 22h ago
  • Water temp22.2°C
  • ClarityClear
Today's fly
Parachute Adams
Parachute Adams12-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.69 m
Last reading 22h ago
Water temp22.2°C
ClarityClear
Weather25°C
WindSE 11 km/h
Pressure1013 hPa
Rain · recent2.5 mm
Rain · ahead0.0 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for Rainbow Trout
Warm — slow
22°C est.ideal 10–18°C
0°14°28°
How to fish it · for Rainbow Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Water at 22.2°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day

Hatch predictions

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 with Pro.

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Evidence
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
2
1
1
2
2
2
2
2
2
2
Western Green DrakeHatch
2
2
Flav (Small Western Green Drake)Hatch
2
3
2
Mahogany DunHatch
2
2
American March BrownHatch
2
3
2

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
  • Montana licence
  • Check FWP for hoot-owl (afternoon) closures on the lower river in hot summers.
What's coming
Plan ahead
5-day outlook
Water here around 22°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Wide view of a gravel road crossing the Clark Fork River on a bridge, with a road sign reading Clark Fork River, cottonwoods and mountains in the background
    The Clark Fork River, Powell County, Montana
  2. Terrain map of the venue
    Terrain map
About this water

The Clark Fork is a river with a hard past — the upper reaches carried a century of mining poison out of Butte, and what you fish today is the product of an enormous cleanup. Below Missoula it's grown back into a big, broad freestone full of browns and rainbows that eat trico and baetis and a fine fall caddis. It's a float river in its lower reaches and a wade river up high. Like most things around here it goes brown in June runoff and then settles into a long, generous summer and fall.

  • Mixed
Water quality · US Clean Water Act
  • Aquatic life: Impaired
  • Recreation: Impaired
What this classification means

Recreation: Bacteria/pathogen advisory — mind wading cuts and immersion.

EPA ATTAINS assessment unit 'Clark Fork River' (MT76E001_010), 2021 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Nutrients, Algal Growth, Habitat Alterations, Metals Other Than Mercury, Mercury. This is a Clean Water Act assessment-unit classification (the US analogue of WFD), not a live reading.

Status is for the Clean Water Act assessment unit covering this reach.

EPA ATTAINS (Clean Water Act) · MT76E001_010

The full read · show the working · for Rainbow Trout · confidence 90%
How the 15 is built — score × weight = contribution
Temperature9 × 28%2.5
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time40 × 13%5.2
Pressure75 × 7%5.3
Insect activity57 × 12%6.8
Limiting factor: Water temperature (22.2°C) is outside Rainbow Trout's preferred range (10–18°C)= 53
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–18 °C ideal band — would lift the score and ease welfare.
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • TroutThird Saturday of May → Last day of February
Related guides
Euro Nymphingsubsurface methods
Booking & contacts