Waters · United States
South Fork Snake River (Irwin) fishing report
Updated Friday, 9 October 2026 · refreshed automatically through the day
Below Palisades Dam the South Fork is one of the last strongholds of native Yellowstone cutthroat, fished from drift boats through a cottonwood canyon. Releases spike hard in irrigation season.
Today's report: excellent (80/100)
Brown Trout is the most promising species on South Fork Snake River (Irwin) today. Water temperature is around 16.2°C and barometric pressure is stable. Gauge SNAKE RIVER NR IRWIN ID shows the water level falling (1 cm/24h).
South Fork Snake River (Irwin) water temperature and flow
- Discharge: 115.2 m³/s (4,068 cfs) — down 1% over 24 hours
- Level trend: falling (1 cm/24h)
Measured at gauge SNAKE RIVER NR IRWIN ID · reading 62 min ago. Published by the national hydrological service, not estimated by us.
Best time to fish today
- 00:00–02:00 local time — score 87/100
- 08:00–10:00 local time — score 87/100
- 18:00–20:00 local time — score 84/100
3-day outlook by species
| Species | Friday 9 Oct | Saturday 10 Oct | Sunday 11 Oct |
|---|---|---|---|
| Rainbow Trout | 76 — good | 83 — excellent | 83 — excellent |
| Brown Trout | 80 — excellent | 88 — excellent | 89 — excellent |
Why this score
Cast & Scan uses a deterministic, published scoring model — no black box. The strongest influences on today's South Fork Snake River (Irwin) rating:
- water temperature: helping (+1)
- solunar period: helping (+1)
- season: helping (+1)
- wind: helping (+0.9)
- precipitation: helping (+0.9)
- river flow: helping (+0.85)
Forecast computed Sat, 10 Oct 2026 03:31:46 GMT · data: Open-Meteo + gauge SNAKE RIVER NR IRWIN ID · refreshed automatically through the day · see our published accuracy
Wondering how this stacks up against the apps you already know? Cast & Scan vs Fishbrain vs BassForecast — an honest comparison, including where they beat us.
Read before you go
- Trout stream tactics, read through the forecast
- How river flow trend changes the bite
- Barometric pressure and fishing, explained
More rainbow trout waters
- Kenai River (Soldotna) — Alaska, USA
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- Animas River (Durango) — Colorado, USA
- Au Sable River (Mio) — Michigan, USA
Nearby waters
- Henry's Fork (Lower) — Idaho, USA (76 km away)
- Madison River (Ennis) — Montana, USA (226 km away)
- Wind River (Boysen) — Wyoming, USA (244 km away)
- Green River (Fontenelle) — Wyoming, USA (250 km away)
- Yellowstone River (Livingston) — Montana, USA (255 km away)
- Big Hole River (Melrose) — Montana, USA (269 km away)