Montana ·
Stillwater River Fly Fishing Report - October 18, 2026
STILLWATER RIVER
ReportOCT 18 — 25, 2026
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Flow
409CFS
Stillwater River near Absarokee, MT
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Water Temp
—
Updated 2026-10-18
☀️
Weather
35–70°F
Mostly Clear
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Clarity
Clear
Check post-storm
The Stillwater is running at 409 CFS with a gauge height of 1.56 ft — low, clear, and highly wade-fishable with excellent access to productive seams. Water temps are in prime fall range, and with mostly sunny skies and a high of 62°F today, expect a solid midday hatch window.
What's Working — Hot Flies
Juju Baetis Tungsten #22
#22
Top Secret Baetis #16
#16
Parachute - Blue Wing Olive #22
#22
Egan's Silver Bullet - Baetis #14
#14
Black Zebra Midge(TBH) #20
#20
Olsen's Hare's Ear Blowtorch Barbless #20 - 28
#20
Egan's Frenchie #12
#12
Egan's Thread Frenchie Jig - Olive #12
#12
Corn-fed Caddis (CDC) Olive #20
#20
Olsen's Straggle Stone Brown Barbless #12 - 32
#12
Tungsten Rainbow Warrior - Extra Heavy #14
#14
Bionic Ant 2.0 - Black #16
#16
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Blue-Winged Olive (Baetis) | #18-22 | Heavy | 11 AM - 3 PM |
| Midge | #20-24 | Moderate | 9 AM - 12 PM |
| Caddis | #16-20 | Light | 2 PM - 5 PM |
| October Caddis | #8-10 | Light | 3 PM - Dusk |
| Stonefly (Little Brown) | #14-16 | Light | 10 AM - 1 PM |
Best Time Window
- 8 AM - 10 AM: Early midge nymphing in tailouts and slow glides before the sun hits the water.
- 11 AM - 2 PM: Prime BWO hatch window — watch for rising fish in flat water and be ready to switch to dries.
- 3 PM - Dusk: Afternoon caddis activity picks up; work bankside structure with a dry or swing a soft hackle through the lower runs.
Guide's Tip
From the benchWith the river at 409 CFS and gin-clear, your approach is everything — stay low, wade slowly, and work upstream. Focus your nymphing in the 2-4 foot seams along current breaks, setting your indicator depth at 1.5x the water depth to keep flies ticking the bottom. When the BWO hatch fires between 11 AM and 2 PM, switch to a dry and target rising fish in the flat water below riffles with a reach cast and a 12-15 foot leader tapered to 6X. Fall browns are beginning to think about spawning, so don't overlook the deeper, slower pools near gravel bars — that's where the big fish are staging.
Main Species
Rainbow Trout
Brown Trout
Yellowstone Cutthroat Trout
