Montana ·
Yellowstone River Fly Fishing Report - August 16, 2026
YELLOWSTONE RIVER
ReportAUG 16 — 23, 2026
🌊
Flow
—CFS
🌡️
Water Temp
—
☀️
Weather
49–80°F
Slight Chance Rain Showers
💧
Clarity
Clear
Check post-storm
Live USGS gauge data is unavailable for today, but recent web intel confirms the Yellowstone was running approximately 2,430 CFS at Corwin Springs with clear water and temperatures in the 66–67°F range — moderate, fishable flows with good clarity typical of mid-August. Afternoon thunderstorms are possible after 1 PM, so plan your day around a strong morning push.
What's Working — Hot Flies
Bionic Hopper - Tan #12
#12
Bionic Hopper - Purple #12
#12
Bionic Ant 2.0 - Black #16
#16
Bionic Ant 2.0 - Brown #12
#12
Tungsten Split Case Nymph - PMD #20
#20
Egan's Thread Frenchie Jig - Olive #12
#12
Parachute - Blue Wing Olive #22
#22
Corn-fed Caddis (CDC) Tan #20
#20
Coffey's CH Sparkle Minnow Sculpin #6
#6
Joe's Mini Crayfish Jig #6
#6
Egan's Frenchie #12
#12
Tungsten Rainbow Warrior - Extra Heavy #14
#14
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Grasshoppers | 10-14 | Heavy | 10 AM - 2 PM |
| Caddis | 16-20 | Moderate | 6 PM - 8 PM |
| PMD (Pale Morning Dun) | 16-20 | Moderate | 9 AM - 12 PM |
| Blue-Winged Olive | 20-22 | Light | 12 PM - 3 PM |
| Ants / Terrestrials | 14-18 | Moderate | 11 AM - 3 PM |
Best Time Window
- 6:30 AM - 10:00 AM: Prime hopper and terrestrial window along cutbanks before heat builds — fish are up and aggressive.
- 10:00 AM - 1:00 PM: PMD and ant action peaks in riffles and tailouts; nymph the deeper seams with a Frenchie or Split Case PMD.
- 7:00 PM - Dusk: Evening caddis and spinner fall along riffled edges — CDC Caddis in the film as light fades.
Guide's Tip
From the benchWith afternoon thunderstorms likely after 1 PM, front-load your day hard — be on the water by 7 AM and work grassy cutbanks and willow-lined bends with hoppers and ants while the light is low and fish are aggressive. When the clouds build before the storms, switch to a BWO parachute in the flat tailouts; that overcast window can produce some of the best dry-fly action of the day. If you're still on the water post-storm, tie on the Sparkle Minnow or Crayfish Jig and swing through the deeper boulder runs — the turbulence and low light push big browns into feeding mode. Keep a close eye on water clarity after any storm cell passes upstream.
Main Species
Yellowstone Cutthroat Trout
Brown Trout
Rainbow Trout
