Freestone · Mixed · Montana, US

Flathead River

A calm, glassy stretch of the Flathead River lined with rocky banks and autumn-coloured trees near Glacier National Park, Montana.
Tomorrow · A proper day on the water
Pheasant Tail
Forecast · Tomorrow
A proper day on the water
A proper day for it. Work the seams with an upstream nymph, switch to the dry when they show.
65% projected
Today's fly
Pheasant Tail
Pheasant Tail
Conditions on the water · Tomorrow
Live gauge
Level
Rising
1.30 m
Lifting fast
Water temp10.7°C
ClarityVery coloured
Weather12°C
WindN 8 km/h
Pressure1021 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Cutthroat Trout
Ideal
11°C est.ideal 9–15°C
0°14°28°
How to fish it · for Cutthroat 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
Excellent — water temperature is right today, though time of day could be better.
Likely species
Mayflies
Caddisflies
terrestrials
Hatch timeline · tomorrowPeak at 12pm

12pm(now) — Mahogany Dun

Stage: On emergersApproach: Emerger or dryActivity: 70%
Also:Black Midge24%
Peak emergence windowWeather boostDegree-days at peak7 food groups active

Peak activity at 12pm — Mahogany Dun (Mahogany Dun, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds with Pro.

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Beyond the hatch · worth watchingambient prey(1)

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Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · September 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
Brown DunHatch
2
3
3
3
3
3
3
2
Western Green DrakeHatch
2
2
Flav (Small Western Green Drake)Hatch
2
3
2
Mahogany DunHatch
2
2

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

Ranked for today
Cutthroat Trout fly box
SD
Sex Dungeon
2-6 · Pattern
Proven pattern for this period
Permits & access
Permit required — see local rules.
  • Montana licence
  • Bull trout must not be targeted and must be released (federally threatened)
  • Check FWP and Glacier NP boundary-water rules on the North and Middle forks.
What's coming
Plan ahead
5-day outlook
Gallery · 2
  1. A calm, glassy stretch of the Flathead River lined with rocky banks and autumn-coloured trees near Glacier National Park, Montana.
    Flathead River - Calm Morning
  2. Terrain map of the venue
    Terrain map
Conservation note

Headline fish is native westslope cutthroat (Oncorhynchus clarkii lewisi) — handle minimally and release. Native bull trout (Salvelinus confluentus) are present and federally threatened: targeting is prohibited and any hooked by accident must be released unharmed. The pack's 'cutthroat_trout' species/scoring profile is a Phase 1 deliverable; until seeded it will not score. There is no bull_trout scoring profile by design — it must not be presented as a target species.

Water quality · US Clean Water Act
  • Aquatic life: Not assessed
What this classification means

EPA ATTAINS assessment unit 'Flathead River' (MT76O001_010), 2021 Integrated Report. Aquatic Life use: Not Assessed. 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) · MT76O001_010

The full read · show the working · for Cutthroat Trout · confidence 90%
How the 81 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time55 × 13%7.2
Pressure75 × 7%5.3
Insect activity61 × 12%7.3
Conditions total= 81
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout Third Saturday of May → Last day of February
Related guides
Euro Nymphingsubsurface methods
Booking & contacts