Montana ·
Gallatin River Fly Fishing Report - October 4, 2026

GALLATIN RIVER
ReportOCT 4 — 11, 2026
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Flow
345CFS
Gallatin River near Gallatin Gateway, MT
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Water Temp
—
Updated 2026-10-04
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Weather
38–83°F
Mostly Clear
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Clarity
Clear
Check post-storm
Flow is running at 345 CFS near Gallatin Gateway with a gauge height of 1.36 ft — low, clear, and technical conditions that demand precise presentations and light tippet. A warm, sunny Sunday pushing to 78°F means afternoon Baetis hatches are your best dry-fly window, with nymphing and streamers carrying the morning.
What's Working — Hot Flies

Parachute - Blue Wing Olive #22
#22

Juju Baetis Tungsten #22
#22

Roza's World Spain Perdigon Barbless #18 - 32
#18

Black Zebra Midge(TBH) #20
#20

Olsen's Pheasant Tail Nymph Doppleganger Brown Barbless #24 - 20
#20

Olsen's Straggle Stone Brown Barbless #12 - 32
#12

Egan's Thread Frenchie Jig - Olive #12
#12

Bionic Ant 2.0 - Black #16
#16

Coffey's CH Sparkle Minnow Sculpin #6
#6

Tungsten Jig Bugger - Olive - Barbless #14
#14

Corn-fed Caddis (CDC) Tan #20
#20

Top Secret Baetis #16
#16
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Blue-Winged Olive (Baetis) | #20-22 | Moderate | 12 PM - 4 PM |
| Midge | #20-22 | Heavy | 8 AM - 11 AM |
| Caddis | #16-18 | Light | 4 PM - 6 PM |
| Terrestrials (Ants) | #16 | Light | 11 AM - 2 PM |
| Stonefly (Brown) | #12 | Light | 9 AM - 12 PM |
Best Time Window
- 7 AM - 10 AM: Midge-focused nymphing in slow glassy seams and tailouts before the sun hits the water.
- 12 PM - 4 PM: Prime Baetis hatch window — watch for rising fish in flat water and switch to dries when you see consistent surface activity.
- 5 PM - Dusk: Streamer and caddis hour — swing streamers through deep pools and skate a CDC caddis along the banks as light fades.
Guide's Tip
From the benchWith flows at 345 CFS and gin-clear water, fish will be spooky — approach runs from downstream and stay low. During the midday Baetis window, look for rising fish in the flat tailouts below riffles and present your dry upstream with a reach cast to buy yourself a drag-free drift of at least 4-6 feet. If you're not seeing rises, run a single tungsten nymph tight to the bottom through the deeper canyon slots at a depth of 1.5x the water column — the low, clear conditions mean fish are holding deeper and tighter to structure than you'd expect. Don't overlook the last 90 minutes of light for streamer fishing; big browns are beginning their fall aggression and a sculpin pattern stripped hard through the deepest pools can produce the fish of the season.
Main Species
Brown Trout
Rainbow Trout
Westslope Cutthroat Trout
