Freestone · Mixed · Wyoming

Lamar River

The Lamar River winding through Yellowstone's Lamar Valley

The Lamar Valley, with Slough and Soda Butte feeding in, holds wild, free-rising Yellowstone cutthroat in country that still feels like wilderness.

Marginal · Cutthroat Trout
Parachute Adams · 12-18
Marginallive now
Slow going — pick your moments
River steady at a fishable height. Slow going — pick your moments and do not force it.
80% confidence
What moved it
  • Level0.62 mLast reading 4h ago
  • Water temp17.5°C
  • ClarityClear
Today's fly
Parachute Adams
Parachute Adams12-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.62 m
Last reading 4h ago
Water temp17.5°C
ClarityClear
Weather28°C
WindNW 12 km/h
Pressure1014 hPa
Rain · recent5.4 mm
Rain · ahead0.2 mm

Live readings only. Trends shown where the gauge supports them.

Water temperature for Cutthroat Trout
Warm — slow
17.5°Cideal 915°C
0°14°28°
How to fish it · for Cutthroat Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Water at 17.5°C — above the cutthroat trout caution line (16°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 4 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 2 guilds with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 with Pro.

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Evidence
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Western Green DrakeHatch
2
2
Flav (Small Western Green Drake)Hatch
2
3
2
Mahogany DunHatch
2
2
American March BrownHatch
2
3
2

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Cutthroat Trout fly box
Permits & access
Permit required — see local rules.
  • Yellowstone NP licence and native-cutthroat rules (often barbless catch-and-release) — check current NPS regulations.
What's coming
Plan ahead
5-day outlook
Water here at 17.5°C. Nothing cooler within range.
Gallery · 2
  1. The Lamar River winding through Yellowstone's Lamar Valley
    Lamar River, Yellowstone National Park
  2. Terrain map of the venue
    Terrain map
About this water

The Lamar Valley, with Slough and Soda Butte feeding in, holds wild, free-rising Yellowstone cutthroat in country that still feels like wilderness. It's a terrestrial game from mid- to late summer once the river clears — hoppers, ants, beetles to fish that want to eat off the top. A summer storm can turn it to chocolate milk for days, and there's no arguing with that. This is native-species water under Park regulation; treat the cutthroat as the irreplaceable things they are.

Under the surface

The Lamar runs through the closest thing Yellowstone has to the Serengeti — a wide, open glacial valley of grassland and sage where the bison graze and the wolves work the far slopes. It's a freestone river of the high country, snowmelt-fed and unregulated, brown with runoff into July and then dropping into a clear, gravel-bottomed meander that braids across the valley floor. This is native Yellowstone cutthroat water, and the fish are everything the cutthroat is supposed to be: willing, beautiful, and not always as easy as their reputation when the valley wind is up and they're sipping hoppers along the cut banks. The bed is rounded volcanic cobble and gravel; the banks are grass and undercut sod. Wading is straightforward when the river's down, and the whole business of fishing it is half watching the water and half watching the wildlife.

Wading: High off color runoff into July

  • Mixed
  • Unconfined
  • Pool riffle
  • Meandering
Conservation note

Primary species is native Yellowstone cutthroat (Oncorhynchus clarkii bouvieri). A 'cutthroat_trout' species + scoring profile is a Phase 1 deliverable; until added it will not score.

The full read · show the working · for Cutthroat Trout · confidence 80%
How the 26 is built — score × weight = contribution
Temperature47 × 28%13.2
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time60 × 13%7.8
Pressure75 × 7%5.3
Insect activity64 × 12%7.7
Conditions total= 67
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 9–15 °C ideal band — would lift the score and ease welfare.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
  • TroutSaturday of Memorial Day weekendFirst Sunday in November
Related guides
Booking & contacts