Water temperature for Brown Trout
Warm — slow18.3°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 18.3°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayPeak at 6am
Hatch predictions
Today's headline hatch shown — see all 5 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 2 with Pro.
Start free trial14-day free trial. Cancel anytime.
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
Quill GordonHatch
2
2
Blue QuillHatch
2
3
2
HendricksonHatch
2
2
Eastern March BrownHatch
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
Water here at 18.3°C. Nothing cooler within range.
Gallery · 2
The Au Sable River bends through autumn forest at High Banks Overlook, Michigan Terrain map
The full read · show the working · for Brown Trout · confidence 80%
How the 38 is built — score × weight = contribution
Temperature51 × 28%14.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Conditions total= 68
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Related guides
Booking & contacts
Au Sable River
Water temperature for Brown Trout
Warm — slow18.3°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 18.3°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayPeak at 6am
Hatch predictions
Today's headline hatch shown — see all 5 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 2 with Pro.
Start free trial14-day free trial. Cancel anytime.
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
Quill GordonHatch
2
2
Blue QuillHatch
2
3
2
HendricksonHatch
2
2
Eastern March BrownHatch
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
Water here at 18.3°C. Nothing cooler within range.
Gallery · 2
The Au Sable River bends through autumn forest at High Banks Overlook, Michigan Terrain map
The full read · show the working · for Brown Trout · confidence 80%
How the 38 is built — score × weight = contribution
Temperature51 × 28%14.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Conditions total= 68
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Related guides
Booking & contacts