Yellowstone River Fly Fishing Report - June 21, 2026

Fly Fishing Report

YELLOWSTONE RIVER

Report
JUN 21 — 28, 2026
🌊
Flow
CFS
🌡️
Water Temp
☀️
Weather
45–75°F
Rain Showers Likely
💧
Clarity
Clear
Check post-storm
Live USGS gauge data is unavailable for today's report; per the most recent web intel from June 19, flows were running at approximately 7,100 CFS — steady and fishable, with the Emigrant-to-Pine stretch producing best. Salmonflies and golden stones are the headline hatch right now, and the big-bug window is wide open.
Hatch Chart
Insect Size Activity Prime Time
Salmonfly (Pteronarcys californica) #4-6 Heavy 10 AM - 3 PM
Golden Stonefly #6-8 Heavy 11 AM - 4 PM
Green Drake (Drunella doddsi) #10-12 Moderate 1 PM - 5 PM
PMD (Pale Morning Dun) #16-20 Moderate 10 AM - 1 PM
Caddis #16-20 Light 6 PM - 8 PM
Midge #20-22 Light 7 AM - 9 AM
Best Time Window
  • 7 AM - 10 AM: Pre-sun nymphing with heavy stonefly patterns in the main boulder gardens before boat traffic picks up.
  • 10 AM - 3 PM: Prime salmonfly and golden stone window — fish big dries and nymphs along cut banks and riffles from Emigrant to Pine.
  • 5 PM - 8 PM: Evening caddis and BWO activity in the tail-outs and flats; switch to dry flies as light softens and storm cells clear.
Guide's Tip
From the benchWith salmonflies and golden stones both on the water, focus your morning on the Emigrant-to-Pine stretch and work the big boulder gardens and undercut banks with a heavy stonefly nymph under a large indicator — set your depth so the fly is ticking the bottom. As afternoon approaches and storm cells build, watch for fish to slide into the slower inside seams and flats to intercept PMD and green drake emergers; that's when you want to downsize and slow your drift. If the thunderstorms push through mid-afternoon and the bite goes quiet on the surface, pick up a streamer rod and swing a Sculpzilla or Sparkle Minnow through the deeper pools — post-storm pressure drops often trigger aggressive predatory behavior from the big browns.
Main Species
Yellowstone Cutthroat Trout
Brown Trout
Rainbow Trout
Fly Fish Food
Report generated June 21, 2026 — Next update: June 28, 2026