Freestone · Mixed · Montana

Yellowstone River

Yellowstone River venue image
Poor · Brown Trout
Parachute Adams · 12-18
Poorlive now
Not the day for it
River temperature is the limiting factor today, not the flow. This is not the day to push it. Check the thermal advice above before you head out.
80% confidence
What moved it
  • Level1.02 mDropping after lift
  • Water temp20.5°C
  • ClarityClear
Today's fly
Parachute Adams
Parachute Adams12-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
1.02 m
Dropping after lift
Water temp20.5°C
ClarityClear
Weather25°C
WindE 5 km/h
Pressure1014 hPa
Rain · recent0.2 mm
Rain · ahead0.0 mm

Live readings only. Trends shown where the gauge supports them.

Water temperature for Brown Trout
Warm — slow
20.5°Cideal 10–16°C
0°14°28°
How to fish it · for Brown 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 20.5°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayQuiet day

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
Brown Trout fly box
Permits & access
Permit required — see local rules.
  • Montana licence
  • Frequently unfishable through June runoff
  • Handle native cutthroat gently and release.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Water here at 20.5°C — the fishing's alive, but these are cooler if you'd rather rest the warm water.
Gardner River
45 km
~16°C
Cutthroat trout · Brown trout · Rainbow trout
Gallery · 1
  1. Terrain map of the venue
    Terrain map
Water quality · US Clean Water Act
  • Aquatic life: Impaired
What this classification means

EPA ATTAINS assessment unit 'Yellowstone River' (MT43B003_010), 2021 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Habitat Alterations. 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) · MT43B003_010

The full read · show the working · for Brown Trout · confidence 80%
How the 24 is built — score × weight = contribution
Temperature19 × 28%5.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity56 × 12%6.7
Limiting factor: Water temperature (20.5°C) is outside Brown Trout's preferred range (10–16°C)= 58
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–16 °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