Freestone · Mixed · Montana, US

Jefferson River

A broad, calm stretch of the Jefferson River bordered by grassy banks and cottonwood trees, with mountains in the distance.
Tomorrow · A proper day on the water
Sculpin Streamer
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.
75% projected
Today's fly
Sculpin Streamer
Sculpin Streamer
Conditions on the water · Tomorrow
Live gauge
Level
Steady
1.12 m
Water temp9.7°C
ClarityClear
Weather8°C
WindN 8 km/h
Pressure1017 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 Brown Trout
Cool — slow
10°C est.ideal 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
Excellent — water temperature is working for you, but time of day is the limiting factor today.
Likely species
Mayflies
Chironomids
Gammarids
Hatch timeline · tomorrowPeak at 11:00

12:00(now) — Western Blue-Winged Olive

Stage: On emergersApproach: Emerger or dryActivity: 53%
Also:Black Midge32%
Peak emergence window5 food groups active

Peak activity at 11:00 — Western Blue-Winged Olive (Western Blue-Winged Olive, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 2 guilds as a supporter.

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Supporters see what else is on the menu.

Start free trial

14-day free trial. Cancel anytime.

Evidence
Records-basedModerate confidence

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

Through the year
0–3 scale · October 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
Fly box · Brown Trout
SD
Sex Dungeon
2-6 · Pattern
Proven pattern for this period
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
Other water nearby · 5
Big Hole River
28 km
78
Brown trout · Rainbow trout · Brook trout
Ruby River
33 km
85
Brown trout
Beaverhead River
47 km
81
Brown trout · Rainbow trout
Ennis Lake
52 km
Brown trout · Rainbow trout
Madison River
55 km
77
Brown trout · Rainbow trout
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 75%
How the 82 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity68 × 12%8.2
Conditions total= 82
Can you trust it?
Water temperatureair-to-water estimateestimated
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 Tercer Saturday de May → Último day of February
Related guides
Euro Nymphingsubsurface methods
Booking & contacts