Freestone · Mixed · Montana

Jefferson River

A broad, calm stretch of the Jefferson River bordered by grassy banks and cottonwood trees, with mountains in the distance.
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.
90% confidence
What moved it
  • Level1.10 mLast reading 4h ago
  • Water temp23.3°C
  • ClarityClear
Today's fly
Parachute Adams
Parachute Adams12-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
1.10 m
Last reading 4h ago
Water temp23.3°C
ClarityClear
Weather23°C
WindE 6 km/h
Pressure1013 hPa
Rain · recent0.7 mm
Rain · ahead0.0 mm

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

Water temperature for Brown Trout
Warm — slow
23.3°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 23.3°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 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
  • The Jefferson is one of the first rivers to go under summer hoot-owl restrictions — check FWP before an afternoon session.
What's coming
Plan ahead
5-day outlook
Water here at 23.3°C. Nothing cooler within range.
Gallery · 2
  1. A broad, calm stretch of the Jefferson River bordered by grassy banks and cottonwood trees, with mountains in the distance.
    Jefferson River at Silver Star, Montana
  2. Terrain map of the venue
    Terrain map
Water quality · US Clean Water Act
  • Aquatic life: Impaired
What this classification means

EPA ATTAINS assessment unit 'Jefferson River' (MT41G001_011), 2021 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Temperature, Sediment, Habitat Alterations, Hydrologic Alteration, Metals Other Than 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) · MT41G001_011

The full read · show the working · for Brown Trout · confidence 90%
How the 2 is built — score × weight = contribution
Temperature1 × 28%0.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity41 × 12%4.9
Limiting factor: Water temperature (23.3°C) is outside Brown Trout's preferred range (10–16°C)= 51
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