Mayflies
Stoneflies
Caddisflies
Gammarids
- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR10114
Rules at a glance
- Day tickets
Water temperature for Brown Trout
Ideal11°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.
Likely species
Caddisflies
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 7 active hatches hour by hour as a supporter.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 2 guilds as a supporter.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Supporters see what else is on the menu.
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 · October 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
Alpine RhithrogenaHatch
2
3
3
2
Sculpin / Baitfish (Rivers)Hatch
2
3
3
3
3
3
3
3
2
March BrownHatch
2
3
2
Late March BrownHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Fly box · Brown Trout
Permits & access
Permit required — see local rules.
- AAPPMA permits.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
The Borne river in winter, Pont de Beffay, Petit-Bornand-les-Glières Terrain map
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 90%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity63 × 12%7.6
Conditions total= 83
Can you trust it?
Water temperatureair-to-water estimateestimated
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 2. Saturday im March → 3. Sunday im September
- Grayling 3. Saturday im May → 3. Sunday im 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
Borne
Water temperature for Brown Trout
Ideal11°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.
Likely species
Caddisflies
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 7 active hatches hour by hour as a supporter.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 2 guilds as a supporter.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Supporters see what else is on the menu.
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 · October 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
Alpine RhithrogenaHatch
2
3
3
2
Sculpin / Baitfish (Rivers)Hatch
2
3
3
3
3
3
3
3
2
March BrownHatch
2
3
2
Late March BrownHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Fly box · Brown Trout
Permits & access
Permit required — see local rules.
- AAPPMA permits.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
The Borne river in winter, Pont de Beffay, Petit-Bornand-les-Glières Terrain map
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · FRDR10114
The full read · show the working · for Brown Trout · confidence 90%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity63 × 12%7.6
Conditions total= 83
Can you trust it?
Water temperatureair-to-water estimateestimated
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 2. Saturday im March → 3. Sunday im September
- Grayling 3. Saturday im May → 3. Sunday im 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