- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR492
Rules at a glance
- Day tickets
Water temperature for Brown Trout
Warm — slow18.7°Cideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the open trout season. Spring olives and grannom; sedges through summer evenings; small dark flies into autumn close.
Where
Karst water through the upper Ain valley. Pool tails, glides, and the cushion behind boulders. The Ain is bigger water than the Loue or Doubs — wadeable but demanding.
Method
Upstream dry to spotted rising fish; long fine leader. The water reads clear — careful approach matters more than fly choice. Move slowly upstream, cast accurately, accept the result.
Kit
9 ft #4 or #5 for the bigger water. Floating line, 14 ft leader to 4 to 5 lb fluoro. Polarising glasses.
Why this works
Water at 18.7°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 9 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 3 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
Grayling seasonSeason
1
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Blue Winged OliveHatch
1
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.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 2
Water here at 18.7°C — the fishing's alive, but these are cooler if you'd rather rest the warm water.
Gallery · 2
Neuville-sur-Ain (Ain). Terrain map
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 80%
How the 36 is built — score × weight = contribution
Temperature29 × 28%8.1
Flow80 × 22%17.6
Clarity40 × 18%7.2
Feeding Time50 × 13%6.5
Pressure80 × 7%5.6
Insect activity54 × 12%6.5
Conditions total= 52
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
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
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
Ain
Water temperature for Brown Trout
Warm — slow18.7°Cideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the open trout season. Spring olives and grannom; sedges through summer evenings; small dark flies into autumn close.
Where
Karst water through the upper Ain valley. Pool tails, glides, and the cushion behind boulders. The Ain is bigger water than the Loue or Doubs — wadeable but demanding.
Method
Upstream dry to spotted rising fish; long fine leader. The water reads clear — careful approach matters more than fly choice. Move slowly upstream, cast accurately, accept the result.
Kit
9 ft #4 or #5 for the bigger water. Floating line, 14 ft leader to 4 to 5 lb fluoro. Polarising glasses.
Why this works
Water at 18.7°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 9 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 3 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
Grayling seasonSeason
1
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Blue Winged OliveHatch
1
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.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 2
Water here at 18.7°C — the fishing's alive, but these are cooler if you'd rather rest the warm water.
Gallery · 2
Neuville-sur-Ain (Ain). Terrain map
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR492
The full read · show the working · for Brown Trout · confidence 80%
How the 36 is built — score × weight = contribution
Temperature29 × 28%8.1
Flow80 × 22%17.6
Clarity40 × 18%7.2
Feeding Time50 × 13%6.5
Pressure80 × 7%5.6
Insect activity54 × 12%6.5
Conditions total= 52
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
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
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