Montana ·
Bighorn River Fly Fishing Report - October 4, 2026
BIGHORN RIVER
ReportOCT 4 — 11, 2026
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Flow
1810CFS
Bighorn R bl Yellowtail Afterbay Dam nr St. Xavier
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Water Temp
—
Updated 2026-10-03
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Weather
44–87°F
Partly Cloudy
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Clarity
Clear
Check post-storm
Flow is running at 1,810 CFS (gauge height 60.74 ft) — up from last week's 1,490 CFS but still within a fishable, wadeable range with the excellent clarity that's been the hallmark of this stretch all fall. Sunday's sunny skies and a high of 76°F will warm the water nicely through midday, setting up a textbook Pseudo hatch window in the afternoon.
What's Working — Hot Flies
Parachute - Blue Wing Olive #22
#22
Egan's CDC Rainbow Warrior #22
#22
Juju Baetis Tungsten #22
#22
Olsen's Peacock Blowtorch Barbless #22 - 24
#22-24
Olsen's Quilldigon - Olive - Barbless #22 - 24
#22-24
Black Zebra Midge(TBH) #20
#20
Roza's World Spain Perdigon Barbless #18 - 32
#18-20
Egan's Thread Frenchie Jig - Olive #12
#12
Coffey's CH Sparkle Minnow Sculpin #6
#6
Tungsten Jig Bugger - Olive - Barbless #14
#14
Corn-fed Caddis (CDC) Olive #20
#20
Egan's Silver Bullet - Baetis #14
#14
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Pseudocleon (Tiny Blue-Winged Olive / Pseudo) | 20-22 | Moderate | 12 PM - 4 PM |
| Blue-Winged Olive (Baetis) | 20-22 | Light | 10 AM - 1 PM |
| Midge | 20-24 | Moderate | 8 AM - 11 AM |
| Caddis | 16-18 | Light | 5 PM - 7 PM |
| Sculpin / Baitfish (streamer forage) | 4-6 | Moderate | 7 AM - 10 AM |
Best Time Window
- 7 AM - 10 AM: Low-light streamer window — work sculpin and bugger patterns along undercut banks and deep outside bends before the sun climbs.
- 12 PM - 4 PM: Prime Pseudo and BWO hatch window — switch to dries and emergers in the flat tailouts as surface activity builds under the warm afternoon sun.
- 5 PM - 7 PM: Evening caddis and midge activity — fish CDC caddis patterns along foam lines as light fades and fish return to the surface.
Guide's Tip
From the benchWith flows bumped up to 1,810 CFS, focus your nymphing efforts in the inside seams and soft water adjacent to the main current — fish have moved slightly off the fastest threads to conserve energy. Set your indicator depth to get your flies ticking the bottom at 2.5 to 3.5 feet, and use a heavier anchor fly like the Perdigon or Thread Frenchie to stay in the zone. When the Pseudo hatch fires between noon and 4 PM, switch to a long, fine tippet (6X) and target the flat tailouts where fish will be sipping in the film — approach from downstream and keep your casts short and accurate. If you're floating, don't overlook the first two hours of daylight with a sculpin pattern tight to the banks; the warming trend this week has big browns actively hunting before the sun gets high.
Main Species
Brown Trout
Rainbow Trout
Mountain Whitefish
