- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR362A
Rules at a glance
- Day tickets
Water temperature for Brown Trout
Cool — slow8°C est.ideal 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
Good — river flow is right today, though insect activity could be better.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 6 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
See the full sub-surface read with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
See what else is on the menu with Pro.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalHigh confidence
Backed by regional invertebrate surveys; no sampling on this exact reach yet.
Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
The River Arly near Césarches, Savoie Terrain map
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 75%
How the 75 is built — score × weight = contribution
Temperature68 × 28%19.0
Flow95 × 22%20.9
Clarity75 × 18%13.5
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity48 × 12%5.8
Conditions total= 75
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Isère (Combe de Savoie)proxy
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Warmer water — toward the 10–16 °C ideal band — would lift the temperature score.
Directions
Seasons & zones
- Trout 2nd Saturday of March → 3rd Sunday of September
Related guides
Booking & contacts
Permits & access
Clubs & associations
Arly
Water temperature for Brown Trout
Cool — slow8°C est.ideal 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
Good — river flow is right today, though insect activity could be better.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 6 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
See the full sub-surface read with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
See what else is on the menu with Pro.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalHigh confidence
Backed by regional invertebrate surveys; no sampling on this exact reach yet.
Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
The River Arly near Césarches, Savoie Terrain map
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR362A
The full read · show the working · for Brown Trout · confidence 75%
How the 75 is built — score × weight = contribution
Temperature68 × 28%19.0
Flow95 × 22%20.9
Clarity75 × 18%13.5
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity48 × 12%5.8
Conditions total= 75
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Isère (Combe de Savoie)proxy
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Warmer water — toward the 10–16 °C ideal band — would lift the temperature score.
Directions
Seasons & zones
- Trout 2nd Saturday of March → 3rd Sunday of September
Related guides
Booking & contacts
Permits & access
Clubs & associations