Spring Creek · Mixed · Idaho

Warm River

Warm River venue image

The Warm River is a small, spring-fed tributary up near Ashton that runs cold and clear and stays fishable when the freestones around it are blown out.

Poor · Rainbow Trout
Green Drake · 10-12
Poorlive now
Not the day for it
Low and clear — careful approach country. A morning for the obvious fish only.
90% confidence
What moved it
  • LevelDry recentlyNo gauge reading
  • Water temp22.2°C
  • ClarityClear
Today's fly
Green Drake
Green Drake10-12
High-confidence seasonal pick
Conditions on the water
Estimate
Level
Dry recently
No gauge reading
Water temp22.2°C
ClarityClear
Weather24°C
WindW 7 km/h
Pressure1012 hPa
Rain · recent0.3 mm
Rain · ahead0.0 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

Water temperature for Rainbow Trout
Warm — slow
22°C est.ideal 10–18°C
0°14°28°
How to fish it · for Rainbow 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 22.2°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day

Hatch predictions

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Sub-surface · on the nymphunder the surface

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
Western Blue-Winged OliveHatch
2
3
3
3
3
3
3
3
2
Pale Morning DunHatch
2
3
3
2
TricoHatch
2
3
2
Freshwater ShrimpHatch
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
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
  • Idaho licence
  • Easy-access family water; check Idaho Fish & Game for reach regulations.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Probably above the Rainbow Trout safety line — these are likely cooler, but carry a thermometer.
Henrys Fork
33 km
~10°C
Rainbow trout
Gallery · 1
  1. Terrain map of the venue
    Terrain map
About this water

The Warm River is a small, spring-fed tributary up near Ashton that runs cold and clear and stays fishable when the freestones around it are blown out. It's a family kind of place — easy access, a campground, eager rainbows and brookies that don't demand much of you, and a stretch where the hatchery presence keeps the catching honest. It won't change your life, but it's a fine, friendly little stream for an afternoon when you want fish in hand more than a story to tell.

  • Mixed
Water quality · US Clean Water Act
  • Aquatic life: Impaired
What this classification means

EPA ATTAINS assessment unit 'Warm River - Warm River Spring to mouth' (ID17040202SK002_04), 2022 Integrated Report. Aquatic Life use: Not Supporting. Listed impairment causes: Temperature. 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) · ID17040202SK002_04

The full read · show the working · for Rainbow Trout · confidence 90%
How the 15 is built — score × weight = contribution
Temperature9 × 28%2.5
Flow60 × 22%13.2
Clarity85 × 18%15.3
Feeding Time40 × 13%5.2
Pressure75 × 7%5.3
Insect activity47 × 12%5.6
Limiting factor: Water temperature (22.2°C) is outside Rainbow Trout's preferred range (10–18°C)= 47
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–18 °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
  • TroutSaturday of Memorial Day weekend → 30 November
Related guides
Euro Nymphingsubsurface methods
Booking & contacts