Freestone · Mixed · Haute-Savoie / Savoie

Arly

A wide alpine river flows over a gravel bed between forested banks, with mountains rising in the background near Césarches, Savoie, France.

The Arly comes down off the Aravis fast and cold, gathering snowmelt through spring before slowing enough in its middle reaches to become properly fishable.

Marginal · Brown Trout
Small Perdigón · 16-20
New ruleReported 1 Aug 2026

Severe drought restrictions (alerte renforcée) in force

The Fier zone (Dept 74) is at alerte renforcée — the second-highest French drought tier — under a préfectoral arrêté. Fishing itself is not named as prohibited, but water is severely restricted and flows are likely very low; fish with care and check locally.

Arrêté préfectoral n°37507

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date. Always confirm locally before travelling.

Marginallive now
Slow going — pick your moments
River temperature is the limiting factor today, not the flow. Fish dawn or dusk if you go at all, and handle everything with extra care.
80% confidence
What moved it
  • LevelProxyvia Isère (Combe de Savoie)
  • Water temp20.0°C
  • ClarityClear
Today's fly
Small Perdigón
Small Perdigón16-20
Euro-nymph
Conditions on the water
Proxy gauge
Level
Falling
Proxy
via Isère (Combe de Savoie)
Water temp20.0°C
ClarityClear
Weather23°C
WindW 9 km/h
Pressure1023 hPa
Rain · recent4.7 mm
Rain · ahead1.4 mm

No gauge on this water — conditions are inferred from Isère (Combe de Savoie). The trend transfers, the absolute level does not.

Water temperature for Brown Trout
Warm — slow
20°C est.ideal 1016°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.
Why this works
Water at 20°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayPeak at 5pm

Hatch predictions

Today's headline hatch shown — see all 8 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

See the full sub-surface read with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 with Pro.

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Evidence
Survey-backed · regionalModerate confidence

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

Updated 13 hours ago

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
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Brown Trout fly box

French nymph-first water. Fast current, technical presentation, weighted nymphs and emergers, with dry flies when fish rise.

What's coming
Plan ahead
5-day outlook
Water here around 20°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. A wide alpine river flows over a gravel bed between forested banks, with mountains rising in the background near Césarches, Savoie, France.
    The River Arly near Césarches, Savoie
  2. Terrain map of the venue
    Terrain map
About this water

The Arly comes down off the Aravis fast and cold, gathering snowmelt through spring before slowing enough in its middle reaches to become properly fishable. You want it in late June through July — that short window after the runoff has cleared and before the summer drawdown bites. The fish are wild browns, small but vigorous, in pocket water and short plunge pools that reward a short line and a heavy nymph. Don't come expecting length; this is an intimate river in a big landscape, and the pleasure is in reading the water rather than covering it. The upper valley around Ugine is the postcard country; the lower reaches towards Albertville warm by August and the fishing moves upstream. Bring a 9ft 4-weight for the middle river and a shorter rod for the headwaters.

  • Mixed
Water quality (WFD)
  • EcologyGood
  • ChemicalUnknown

WFD classification · FRDR362A

The full read · show the working · for Brown Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature25 × 28%7.0
Flow95 × 22%20.9
Clarity95 × 18%17.1
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity65 × 12%7.8
Conditions total= 66
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Isère (Combe de Savoie)proxy
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 March3rd Sunday of September
Related guides
Booking & contacts
Clubs & associations