- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR361A
Rules at a glance
- Day tickets
Water temperature for Brown Trout
Ideal15.1°Cideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the open trout season — late spring through autumn. The Arc is glacial-fed from Haute Maurienne; fishes once meltwater eases.
Where
Pool tails and pocket water through the Maurienne valley. Glacial Alpine freestone — clear cold water, intimate scale.
Method
Upstream dry to risers; dry-dropper through the riffles. The water reads clear — long leader, fine tippet. Move slowly, cast accurately.
Kit
9 ft #4 — French freestone default. Floating line, 12 ft leader to 4 to 5 lb fluoro. Studded boots.
Why this works
Good — water temperature is working for you, but water clarity is the limiting factor today.
Hatch timeline · todayPeak at 6am
Hatch predictions
Today's headline hatch shown — see all 10 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 · regionalModerate 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
Grayling seasonSeason
1
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
Permits & access
Permit required — see local rules.
- Carte de pêche AAPPMA de Savoie.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 75%
How the 76 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow95 × 22%20.9
Clarity40 × 18%7.2
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity62 × 12%7.4
Conditions total= 76
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout 2nd Saturday of March → 3rd Sunday of September
- Grayling 3rd Saturday of May → 3rd Sunday of September
France national rule: grayling opens 3rd Saturday of May in all waters. In 1st category (salmonid) rivers, grayling closes with the trout season on the 3rd Sunday of September. Departmental regulations may impose additional restrictions. Always check the relevant département's 2026 arrêté préfectoral.
Related guides
Booking & contacts
Arc
Water temperature for Brown Trout
Ideal15.1°Cideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the open trout season — late spring through autumn. The Arc is glacial-fed from Haute Maurienne; fishes once meltwater eases.
Where
Pool tails and pocket water through the Maurienne valley. Glacial Alpine freestone — clear cold water, intimate scale.
Method
Upstream dry to risers; dry-dropper through the riffles. The water reads clear — long leader, fine tippet. Move slowly, cast accurately.
Kit
9 ft #4 — French freestone default. Floating line, 12 ft leader to 4 to 5 lb fluoro. Studded boots.
Why this works
Good — water temperature is working for you, but water clarity is the limiting factor today.
Hatch timeline · todayPeak at 6am
Hatch predictions
Today's headline hatch shown — see all 10 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 · regionalModerate 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
Grayling seasonSeason
1
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
Permits & access
Permit required — see local rules.
- Carte de pêche AAPPMA de Savoie.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR361A
The full read · show the working · for Brown Trout · confidence 75%
How the 76 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow95 × 22%20.9
Clarity40 × 18%7.2
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity62 × 12%7.4
Conditions total= 76
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout 2nd Saturday of March → 3rd Sunday of September
- Grayling 3rd Saturday of May → 3rd Sunday of September
France national rule: grayling opens 3rd Saturday of May in all waters. In 1st category (salmonid) rivers, grayling closes with the trout season on the 3rd Sunday of September. Departmental regulations may impose additional restrictions. Always check the relevant département's 2026 arrêté préfectoral.
Related guides
Booking & contacts