- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR545
Rules at a glance
- Day tickets
Water temperature for Grayling
Warm — slow15°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Midday window — grayling feed best from late morning into early afternoon.
Where
Work runs and glides — grayling shoal in the bottom third of the water column.
Method
Tight-line nymph the bottom third with weighted patterns.
Kit
10 ft #3 rod, floating line, long leader to 4 lb fluoro for nymphs.
Why this works
Fair — time of day is right today, though water clarity could be better.
Hatch timeline · todayPeak at 6am
Hatch predictions
Today's headline hatch shown — see all 7 active hatches hour by hour 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
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
Grayling fly box
Permits & access
Permit required — see local rules.
- Réglementation du Parc Naturel Régional du Haut-Jura
- Cartes de pêche AAPPMA
- Quelques parcours en mouche seule et no-kill — à vérifier localement à Mijoux et Bellegarde.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 1
Terrain map
Water quality (WFD)
The full read · show the working · for Grayling · confidence 65%
How the 57 is built — score × weight = contribution
Temperature48 × 28%13.4
Flow55 × 22%12.1
Clarity45 × 18%8.1
Feeding Time90 × 13%11.7
Pressure80 × 7%5.6
Insect activity47 × 12%5.6
Conditions total= 57
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 4–14 °C ideal band — would lift the score and ease welfare.
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
Valserine
Water temperature for Grayling
Warm — slow15°C est.ideal 4–14°C
0°14°28°
How to fish it · for Grayling
When
Midday window — grayling feed best from late morning into early afternoon.
Where
Work runs and glides — grayling shoal in the bottom third of the water column.
Method
Tight-line nymph the bottom third with weighted patterns.
Kit
10 ft #3 rod, floating line, long leader to 4 lb fluoro for nymphs.
Why this works
Fair — time of day is right today, though water clarity could be better.
Hatch timeline · todayPeak at 6am
Hatch predictions
Today's headline hatch shown — see all 7 active hatches hour by hour 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
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
Grayling fly box
Permits & access
Permit required — see local rules.
- Réglementation du Parc Naturel Régional du Haut-Jura
- Cartes de pêche AAPPMA
- Quelques parcours en mouche seule et no-kill — à vérifier localement à Mijoux et Bellegarde.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 1
Terrain map
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR545
The full read · show the working · for Grayling · confidence 65%
How the 57 is built — score × weight = contribution
Temperature48 × 28%13.4
Flow55 × 22%12.1
Clarity45 × 18%8.1
Feeding Time90 × 13%11.7
Pressure80 × 7%5.6
Insect activity47 × 12%5.6
Conditions total= 57
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 4–14 °C ideal band — would lift the score and ease welfare.
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