Montana ·
Bighorn River Fly Fishing Report - July 26, 2026
BIGHORN RIVER
ReportJUL 26 — AUG 2, 2026
🌊
Flow
1500CFS
Bighorn R bl Yellowtail Afterbay Dam nr St. Xavier
🌡️
Water Temp
—
Updated 2026-07-25
☀️
Weather
67–97°F
Partly Cloudy
💧
Clarity
Clear
Check post-storm
Flow is holding steady at 1,500 CFS with gauge height at 59.48 ft — ideal, fishable conditions with excellent water clarity throughout the system. Expect some moss below the 3-Mile access, but it's manageable; heat will push fish into shade and current seams by midday with a high near 97°F and a 30% chance of afternoon thunderstorms.
What's Working — Hot Flies
Black Zebra Midge(TBH) #20
#20
Juju Baetis Tungsten #22
#22
Tungsten Split Case Nymph - PMD #20
#20
Stealth Link Mercer - PMD #20
#20
Parachute - Blue Wing Olive #22
#22
Roza's World Spain Perdigon Barbless #18 - 32
#18
Egan's Thread Frenchie Jig - Olive #12
#12
Egan's Frenchie #12
#12
Bionic Ant 2.0 - Black #16
#16
Corn-fed Caddis (CDC) Tan #20
#20
Coffey's CH Sparkle Minnow Sculpin #6
#6
Tungsten Rainbow Warrior - Extra Heavy #14
#14
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Midge | 20-22 | Heavy | 7 AM - 10 AM |
| Blue-Winged Olive (Baetis) | 20-22 | Moderate | 9 AM - 12 PM |
| PMD (Pale Morning Dun) | 18-20 | Moderate | 10 AM - 1 PM |
| Caddis | 18-20 | Light | 6 PM - 8 PM |
| Terrestrials (Ants) | 14-16 | Moderate | 11 AM - 4 PM |
| Sculpin / Baitfish | 4-6 | Light | 6 AM - 8 AM |
Best Time Window
- 6:30 AM - 10:00 AM: Prime nymphing and BWO dry-fly window before heat builds; fish are active and feeding aggressively in riffles and seam edges.
- 10:00 AM - 1:00 PM: PMD emerger action in the flats; switch to split-case and Mercer PMD nymphs just below the surface film as fish key on emerging duns.
- 6:30 PM - 8:30 PM: Evening terrestrial and caddis bite along grassy banks; cooler temps after potential afternoon storms can trigger some of the best dry-fly action of the day.
Guide's Tip
From the benchWith a high of 97°F today, water temps will climb through the afternoon — get on the water by 6:30 AM and focus your nymphing in the deeper, shaded runs along the east bank where fish will stack up to stay cool. Set your indicator so your flies are ticking the bottom at 4–6 feet in the main channel seams; the Bighorn's clear water means a long, fine tippet (5X or 6X) is non-negotiable. If afternoon thunderstorms fire between 3–5 PM, get off the water and wait them out — the post-storm window with dropping light and cooler air often triggers a strong evening caddis and terrestrial bite along the banks. Watch for moss fouling your flies below 3-Mile and check your point fly every few drifts.
Main Species
Brown Trout
Rainbow Trout
Mountain Whitefish
