Southwestern Montana
SOUTHWESTERN MONTANA
ReportSEP 30 — OCT 7, 2026
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Flow
665CFS
Madison River bl Hebgen Lake nr Grayling MT
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Water Temp
58.5°F
Updated 2026-09-30
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Weather
38–67°F
Sunny
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Reported By
Bruce Staples
On the water
The Madison River below Hebgen Lake is running 665 CFS at 58.5°F under sunny skies, with the Hoot Owl restriction between Hebgen Lake and the Yellowstone Park boundary now lifted. Expect comfortable fishing temperatures through the week with highs in the mid-to-upper 60s and light winds.
From the ShopBruce Staples · September 30, 2026
Terrestrial insect patterns work best during daytime hours on the Madison River, with caddis life cycle patterns taking over during afternoons. The Hoot Owl restriction on the river between Hebgen Lake and the Yellowstone Park boundary has been lifted.
Brown and rainbow trout are migrating from Hebgen Lake into the Madison River within Yellowstone Park. Streamer fishing early in the day is the best strategy for encountering these trout.
The river from the Highway 191 bridge down to Hebgen Reservoir can become crowded with anglers throughout the day.
What's Working — Hot Flies
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Terrestrials (Ants & Hoppers) | #10–16 | Active | Midday through afternoon |
| Caddis (Adults & Emergers) | #12–20 | Active | Afternoon |
| Migrating Trout (Streamer Opportunity) | #4–6 | Active | Early morning |
Best Time Window
- EARLY MORNING (first light to 9 AM): Streamer fishing in the Yellowstone Park section for migrating brown and rainbow trout pushing out of Hebgen Lake
- MIDDAY TO EARLY AFTERNOON (9 AM to 2 PM): Terrestrial patterns — hoppers and ants — along the Madison during peak daytime activity
- AFTERNOON (2 PM to dark): Caddis life cycle patterns as adult and emerger activity takes over on the river
Guide's Tip
From the benchGet on the water early and throw streamers in the Yellowstone Park section of the Madison to target migrating browns and rainbows fresh out of Hebgen Lake — these fish are aggressive and looking to eat. Once the sun gets up, switch to terrestrials for the daytime grind, then transition to caddis life cycle patterns as the afternoon rolls in. If you're fishing the stretch from the Highway 191 bridge down to Hebgen Reservoir, plan to arrive early or late to beat the crowds.
Main Species
Brown Trout
Rainbow Trout
Mountain Whitefish
