Freestone · Sand Gravel · Michigan, US

Au Sable River

Aerial view of the Au Sable River winding through forested banks in autumn, Michigan
Marginal · Brown Trout
Blue Winged Olive · 16-20
Marginallive now
Slow going — pick your moments
River temperature is the limiting factor today, not the flow. Fish dawn or dusk if you go at all, and handle everything with extra care.
80% confidence
What moved it
  • Level1.02 mLast reading 4h ago
  • Water temp19.2°C
  • ClarityClear
Today's fly
Blue Winged Olive
Blue Winged Olive16-20
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
1.02 m
Last reading 4h ago
Water temp19.2°C
ClarityClear
Weather22°C
WindSW 19 km/h
Pressure1012 hPa
Rain · recent28.8 mm
Rain · ahead13.4 mm

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

Water temperature for Brown Trout
Warm — slow
19.2°Cideal 10–16°C
0°14°28°
How to fish it · for Brown 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 19.2°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Likely species
Mayflies
Caddisflies
terrestrials
Hatch timeline · todayPeak at 7am

Hatch predictions

Today's headline hatch shown — see all 6 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

See the full sub-surface read with Pro.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 2 with Pro.

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Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Brown DunHatch
2
3
3
3
3
3
3
2
Quill GordonHatch
2
2
Blue QuillHatch
2
3
2
HendricksonHatch
2
2

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

Ranked for today
Brown Trout fly box
Local fly shops: Gates Au Sable Lodge
Permits & access
Permit required — see local rules.
  • Michigan licence
  • The upper Holy Water is flies-only, no-kill — verify MI DNR rules by reach
  • Lower-river runs are an introduced, harvestable sport fishery.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Water here at 19.2°C — the fishing's alive, but these are cooler if you'd rather rest the warm water.
Rifle River
56 km
~19°C
Steelhead · Chinook salmon · Coho salmon
Gallery · 2
  1. Aerial view of the Au Sable River winding through forested banks in autumn, Michigan
    The Au Sable River bends through autumn forest at High Banks Overlook, Michigan
  2. Terrain map of the venue
    Terrain map
The full read · show the working · for Brown Trout · confidence 80%
How the 33 is built — score × weight = contribution
Temperature22 × 28%6.2
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity63 × 12%7.6
Limiting factor: Water temperature (19.2°C) is outside Brown Trout's preferred range (10–16°C)= 65
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 10–16 °C ideal band — would lift the score and ease welfare.
Related guides
Euro Nymphingsubsurface methods
Booking & contacts