Tailwater · Mixed · Montana

Sun River

Sun River venue image

The Sun comes off the Rocky Mountain Front below Gibson Dam and runs down toward Great Falls, and it's a river ruled by the irrigation calendar.

Prime · Brown Trout
Sparkle Dun · 14-18
Primelive now
About as good as it gets
River dropping into shape after a lift. The kind of afternoon you remember — a weighted nymph through the clearing seams, the dry as it settles.
90% confidence
What moved it
  • Level0.76 mDropping after lift
  • Water temp10.3°C
  • ClarityClear
Today's fly
SD
Sparkle Dun14-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.76 m
Dropping after lift
Water temp10.3°C
ClarityClear
Weather15°C
WindW 9 km/h
Pressure1014 hPa
Rain · recent13.8 mm
Rain · ahead0.0 mm

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

Water temperature for Brown Trout
Ideal
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 right today, though time of day could be better.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 3 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds with Pro.

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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
1
2
2
2
2
2
2
2
2
2
2
1
Western Blue-Winged OliveHatch
2
3
3
3
3
3
3
3
2
Pale Morning DunHatch
2
3
3
2
TricoHatch
2
3
2
Black MidgeHatch
2
3
3
3
3
3
3
3
3
3
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
  • Flow is irrigation-release controlled; the lower river draws down badly in summer.
What's coming
Plan ahead
5-day outlook
Other water nearby · 2
Dearborn River
47 km
Rainbow trout · Brown trout · Cutthroat trout
Missouri River
56 km
Rainbow trout · Brown trout
Gallery · 1
  1. Terrain map of the venue
    Terrain map
About this water

The Sun comes off the Rocky Mountain Front below Gibson Dam and runs down toward Great Falls, and it's a river ruled by the irrigation calendar. The upper reaches below the dam hold good browns and rainbows in cold, clear water; the lower river gets sucked down for the farms come summer and isn't worth your time when it's low and warm. What the dam lets out is the hand you play. Fish the upper water in the cool months and watch the release before you make the drive.

  • Mixed
The full read · show the working · for Brown Trout · confidence 90%
How the 84 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity70 × 12%8.4
Conditions total= 84
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
  • Trout1 January → 31 December
Related guides
Euro Nymphingsubsurface methods
Booking & contacts