Freestone · Mixed · Wyoming

Gardner River

The Gardner River flowing over a rocky bed through an open valley with autumn-colored cottonwoods in Yellowstone.

The Gardner is a steep, pretty little Park freestone that drops fast from the high country down to meet the Yellowstone at Gardiner, and it punches well above its size.

Poor · Rainbow Trout
Parachute Adams · 12-18
Poorlive now
Not the day for it
River steady at a fishable height. Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
90% confidence
What moved it
  • Level0.65 mLast reading 2h ago
  • Water temp22.0°C
  • ClarityClear
Today's fly
Parachute Adams
Parachute Adams12-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.65 m
Last reading 2h ago
Water temp22.0°C
ClarityClear
Weather24°C
WindE 9 km/h
Pressure1015 hPa
Rain · recent1.0 mm
Rain · ahead0.0 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for Rainbow Trout
Warm — slow
22°C est.ideal 1018°C
0°14°28°
How to fish it · for Rainbow 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 22°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day

Hatch predictions

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 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
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
  • Yellowstone NP licence and special regulations
  • Native-cutthroat catch-and-release rules apply on the upper reaches.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Probably above the Rainbow Trout safety line — these are likely cooler, but carry a thermometer.
Gallery · 2
  1. The Gardner River flowing over a rocky bed through an open valley with autumn-colored cottonwoods in Yellowstone.
    Gardner River
  2. Terrain map of the venue
    Terrain map
About this water

The Gardner is a steep, pretty little Park freestone that drops fast from the high country down to meet the Yellowstone at Gardiner, and it punches well above its size. The upper reaches above Osprey Falls hold native cutthroat in genuine backcountry; the lower canyon below Mammoth runs brown trout and rainbows in pocket water you scramble to reach. There's geothermal water feeding in near the old Boiling River, which colors the temperature picture. It's a hike-and-wade, read-the-pockets sort of river, and the cutthroat up top are worth the climb.

  • Mixed
Conservation note

Upper reaches above Osprey Falls hold native cutthroat — barbless catch-and-release under Park rules; handle minimally.

The full read · show the working · for Rainbow Trout · confidence 90%
How the 15 is built — score × weight = contribution
Temperature11 × 28%3.1
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time45 × 13%5.9
Pressure75 × 7%5.3
Insect activity49 × 12%5.9
Limiting factor: Water temperature (22°C) is outside Rainbow Trout's preferred range (10–18°C)= 53
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–18 °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