Lamar River Fly Fishing Report - September 6, 2026

Fly Fishing Report

LAMAR RIVER

Report
SEP 6 — 13, 2026
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Flow
186CFS
Lamar River nr Tower Ranger Station YNP
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Water Temp
59.7°F
Updated 2026-09-06
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Weather
43–78°F
Mostly Clear
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Clarity
Clear
Check post-storm
Flow has dropped to 186 CFS and water temperature is sitting at a prime 59.7°F, meaning the river has shed most of the turbidity from last week's storms and clarity is improving by the hour. Expect fishable, near-clear conditions through the morning with another round of storms possible Sunday night into Labor Day.
Hatch Chart
Insect Size Activity Prime Time
PMD (Pale Morning Dun) #18-20 Moderate 10 AM - 1 PM
Caddis #16-20 Heavy 5 PM - 7 PM
Blue-Winged Olive #20-22 Light 11 AM - 2 PM
Terrestrials (Ants & Hoppers) #12-16 Heavy 11 AM - 4 PM
Midge #20-22 Light 7 AM - 9 AM
Best Time Window
  • 7 AM - 10 AM: Early nymphing in the main channel seams before sun hits the water and fish go shallow.
  • 11 AM - 4 PM: Prime terrestrial window — hoppers and ants along grassy cutbanks in the meadow stretches.
  • 5 PM - 7 PM: Evening caddis hatch in the riffles; get your dry fly on the water before the Sunday night storms roll in.
Guide's Tip
From the benchWith flow down to 186 CFS and clarity improving, focus your morning on the long meadow runs between the Confluence and Soda Butte — wade the inside seams and cast to the far bank where cutthroats are holding in 18–24 inches of water. During the midday terrestrial window, walk the grassy banks and look for subtle sipping rises before you cast; these fish are spooky in low, clear water so stay low and keep your approach from downstream. If the Labor Day storm front pushes through early, switch to a small BWO nymph and slow your drift — fish will drop off the surface and stack up in the soft water just downstream of any current break.
Main Species
Yellowstone Cutthroat Trout
Rainbow Trout
Report generated September 6, 2026 — Next update: September 13, 2026