Freestone · Limestone · Jura-edge / Ain (Varambon–Rhône), FR

Ain (lower / Plaine de l'Ain)

A wide, calm stretch of the River Ain with a gravel bank in the foreground and autumn trees lining the far bank, in the Ain department, France.

The Ain from Varambon to the Rhône confluence flows through limestone with multiple designated no-kill beats and fly-only sections.

Today · Closed season
CDC Emerger
Forecast · Today
Closed season
Out of season. Try elsewhere.
45% projected
Today's fly
CDC Emerger
CDC Emerger
Conditions on the water · Today
Live gauge
Level
Rising
0.01 m
Lifting fast
Water temp11.5°C
ClarityVery coloured
Weather18°C
WindN 17 km/h
Pressure1022 hPa
Rain · recent0.0 mm
Rain · ahead10.1 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Brown Trout
Ideal
12°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
Mayflies
Stoneflies
Caddisflies
Damselflies & dragonflies
Gammarids
Hatch timeline · todayPeak at 6am

12pm(now) — Daddy Long Legs

Stage: On emergersApproach: Emerger or dryActivity: 43%
Also:Heather Fly41%Autumn Olive36%Autumn Needle Fly21%
Weather boostDegree-days at peak12 food groups active

Peak activity at 6am — Daddy Long Legs (Daddy Long Legs, Weather boost)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds as a supporter.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 4 as a supporter.

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Evidence
Survey-backed · regionalHigh confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

Through the year
0–3 scale · September 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

Sight-nymphing and technical dry-fly fishing on very clear trout and grayling rivers, with strong mayfly and sedge windows and highly selective fish.

SS
Small Streamer
6-10 · Pattern
Swing
Permits & access
Permit required — see local rules.
  • AAPPMA permits.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Ain
6.0 km
0
Brown trout · Grayling
Albarine
13 km
Brown trout · Grayling
Chaley Lake
19 km
Brown trout · Rainbow trout
Suran
19 km
Brown trout · Grayling
Domaine des 3 Lacs du Soleil
35 km
Rainbow trout
Gallery · 2
  1. A wide, calm stretch of the River Ain with a gravel bank in the foreground and autumn trees lining the far bank, in the Ain department, France.
    The River Ain near Villieu-Loyes-Mollon, on the lower Ain plain
  2. Terrain map of the venue
    Terrain map
About this water

The Ain from Varambon to the Rhône confluence flows through limestone with multiple designated no-kill beats and fly-only sections. Stable spring-fed character, prolific insect life, selective trout and grayling. Chalk-stream water where presentation matters more than fly choice. Spring through early autumn. Some beats private; public access on certain stretches. Verify local regulations.

Hatches & food

On big regulated trout rivers and tailwaters, altered flow and temperature patterns favour small buzzers, olives and net-spinning caddis over long stretches of the season whenever releases are steady and water is in the right temperature range; scuds and other constant subsurface food matter a lot where weedbeds and steady currents build up, and terrestrials from vegetated margins add surface feeding opportunities largely independent of the exact release schedule.

  • Limestone
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown

WFD classification · FRDR484

The full read · show the working · for Brown Trout · confidence 80%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity73 × 12%8.8
Conditions total= 88
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
Directions
Apple MapsGoogle Maps
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.

  • Coarse 2nd Saturday of March → 3rd Sunday of September

    Chub has no national closed season of its own in France — on a 1st-category (salmonid) reach like this, ALL fishing (any species, any method) is prohibited outside the water's own open season (Code de l'environnement Art. R436-6), so chub simply inherits the trout/grayling season rather than following a separate coarse-fish law.

Related guides
Grayling Playbookgrayling tacticsPyrenees PlaybookFrench riversEuro Nymphingsubsurface methods
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