Southwestern Montana
SOUTHWESTERN MONTANA
ReportOCT 21 — 28, 2026
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Flow
707CFS
Madison River bl Hebgen Lake nr Grayling MT
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Water Temp
52.3°F
Updated 2026-10-20
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Weather
34–59°F
Partly Cloudy
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Reported By
Bruce Staples
On the water
The Madison below Hebgen Lake is running 707 CFS at 52.3°F, with mostly sunny skies and highs near 58–59°F forecast through Thursday — ideal conditions for afternoon caddis activity and productive streamer sessions at first light.
From the ShopBruce Staples · October 21, 2026
It is brown trout time in most of the upper Missouri River drainage. Everywhere, mature brown trout are migrating to spawning areas. Streamers, woolly buggers, and large soft hackles are most effective for encountering these trout.
Top water fishing success is reducing as we advance through autumn, leaving midge activity as the major top water choice for fly fishing action. Weather has reduced bankside terrestrial insect populations.
Caddis life cycle patterns attract trout during afternoons having nice weather. Streamer fishing early in the day or during unsettled weather is the best strategy for encountering these trout.
What's Working — Hot Flies
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Midges | #20–24 | Moderate — primary dry-fly opportunity | Midday through afternoon |
| Caddis | #18–20 | Light — afternoon activity on calm, sunny days | Early to mid-afternoon |
| Terrestrials | #12–16 | Declining — cold weather has reduced bankside populations | Not reliable |
| Streamers / Baitfish (Brown Trout Spawn) | #4–6 | High — spawning browns aggressively responding | Early morning and during unsettled weather |
Best Time Window
- FIRST LIGHT TO MID-MORNING: Prime streamer and woolly bugger time — target runs, banks, and staging areas where spawning browns are holding
- MIDDAY: Midge activity picks up — switch to a two-fly midge rig and focus on slower, glassy water
- EARLY-TO-MID AFTERNOON (NICE WEATHER DAYS): Caddis life cycle patterns come into play — watch for surface activity and fish CDC caddis or emergers along current seams
Guide's Tip
From the benchTime your day around the conditions: get your streamer or woolly bugger in the water at first light when browns are most aggressive, then transition to a midge rig as the sun climbs. On the sunny, calm afternoons forecast for Wednesday and Thursday, switch to a caddis dry or emerger and work the slower current edges. If Madison Losee's report mentions a standard woolly bugger pattern, note that any olive or black woolly bugger in sizes #8–12 will serve the same role as the Tungsten Jig Bugger listed above.
Main Species
Brown Trout
Rainbow Trout
Mountain Whitefish
