Rules at a glance
- Permit required
- Fly only
Water temperature for Brown Trout
Ideal15°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
From the 2nd Saturday of March opening into early September. Best window April–June with small olives and grannom; shoulder through summer.
Where
Upper reaches around La Ferté-Gaucher and upstream towards Esternay. Pool tails, faster glides, and the seams behind overhanging willow on the smaller upper beats.
Method
Upstream dry to risers; dry-dropper through the riffles. Walk-and-spot.
Kit
9 ft #4 (or 8 ft #3 on tighter beats), floating line, 12 ft leader to 3–4 lb fluoro.
Likely species
Gammarids
Hatch timeline · todayPeak at 15:00
Hatch predictions
Today's headline hatch shown — see all 12 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
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
Fly box · Brown Trout
Permits & access
Permit required — see local rules.
- 1ère catégorie above Moulin de Montblin (La Ferté-Gaucher)
- AAPPMA permit + carte de pêche required
- Check the Seine-et-Marne federation's annual notice for category boundaries, catch limits and method restrictions.
What's coming
Plan ahead
5-day outlook
Other water nearby · 2
Gallery · 2
Terrain map
The full read · show the working · for Brown Trout · confidence 75%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time75 × 13%9.8
Pressure80 × 7%5.6
Insect activity49 × 12%5.9
Conditions total= 80
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
Directions
Seasons & zones
- Trout 2.º Saturday de March → 3.º Sunday de September
Related guides
Booking & contacts
Grand Morin (Upper)
Water temperature for Brown Trout
Ideal15°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
From the 2nd Saturday of March opening into early September. Best window April–June with small olives and grannom; shoulder through summer.
Where
Upper reaches around La Ferté-Gaucher and upstream towards Esternay. Pool tails, faster glides, and the seams behind overhanging willow on the smaller upper beats.
Method
Upstream dry to risers; dry-dropper through the riffles. Walk-and-spot.
Kit
9 ft #4 (or 8 ft #3 on tighter beats), floating line, 12 ft leader to 3–4 lb fluoro.
Likely species
Hatch timeline · todayPeak at 15:00
Hatch predictions
Today's headline hatch shown — see all 12 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
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
Fly box · Brown Trout
Permits & access
Permit required — see local rules.
- 1ère catégorie above Moulin de Montblin (La Ferté-Gaucher)
- AAPPMA permit + carte de pêche required
- Check the Seine-et-Marne federation's annual notice for category boundaries, catch limits and method restrictions.
What's coming
Plan ahead
5-day outlook
Other water nearby · 2
Gallery · 2
Terrain map
The full read · show the working · for Brown Trout · confidence 75%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time75 × 13%9.8
Pressure80 × 7%5.6
Insect activity49 × 12%5.9
Conditions total= 80
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
Directions
Seasons & zones
- Trout 2.º Saturday de March → 3.º Sunday de September
Related guides
Booking & contacts