Spate · Slate · Mid Wales / Gwynedd

Dysynni

Photo of Dysynni
Contributor photo

Dysynni

OLU / Wikimedia Commons

Compact upland-to-coast spate from the eastern flank of Cadair Idris through Tal-y-llyn to Tywyn and the bay.

Poor · Atlantic Salmon
Poorlive now
Slow going — better windows ahead
Low and clear — careful approach country. Stale fish in low clear water spook easily — pick your hour.
90% confidence
What moved it
  • Level0.25 mLast reading 12h ago
  • Water temp21.6°C
  • ClarityClear
Conditions on the water
Live gauge
Level
Steady
0.25 m
Last reading 12h ago
Water temp21.6°C
ClarityClear
Weather24°C
WindW 8 km/h
Pressure1020 hPa
Rain · recent0.0 mm
Rain · ahead0.3 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for atlantic salmon
Warm — slow
22°C est.ideal 1014°C
0°14°28°
How to fish it · for atlantic salmon
When
Summer through autumn. Fish on the drop after rain — the Dysynni does not give up fish in low water.
Where
Lower Dysynni pools above the tidal limit at Bryncrug and Tywyn.
Method
Small doubles 10 to 12 across-and-down on a floating line; small tubes on a sink-tip in spring or coloured water. Fish the named lies in each pool, working systematically before moving on. Mandatory catch-and-release under NRW byelaw — every salmon goes back.
Kit
10 ft #7/8 single-hander or 11 ft switch — small spate scale; double-handers are wasted on these rivers. Floating line plus light sink-tip. 10 to 12 lb fluoro tippet.
Why this works
⛔ Water at 21.6°C. This is the line where catch-and-release kills atlantic salmon. Do not fish for them today.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 4 active hatches hour by hour with Pro.

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Evidence
Survey-backed · regionalModerate confidence

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

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Salmon runRun
1
2
2
2
2
2
1
Sea trout runRun
1
2
2
2
2
2
2
1
Trout seasonSeason
1
2
2
2
2
2
1
Daddy Long LegsHatch
2
3
2
March BrownHatch
2
3
2
GrannomHatch
2
2
Large StoneflyHatch
2
3
2

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

What's coming
Plan ahead
5-day outlook
Cooler water nearby · 4
Probably above the atlantic salmon safety line — these are likely cooler, but carry a thermometer.
Gallery · 2
  1. Photo of Dysynni
    Dysynni
  2. Terrain map of the venue
    Terrain map
About this water

Compact upland-to-coast spate from the eastern flank of Cadair Idris through Tal-y-llyn to Tywyn and the bay. Short overall but with proper character — moor water at the top, broader river through the valley, tidal flats at the bottom. Sewin and salmon both run, both classified at risk. The lower river fishes best after a rain pulse drops back into colour; summer low water is for trout and patient observation, not migratory work. Slate and schist bedrock underlie this river. Atlantic salmon are under serious conservation pressure — Natural Resources Wales mandates catch-and-release for salmon on all rivers, so all fish must be returned.

  • Slate
Water quality (WFD)
  • EcologyModerate
  • ChemicalUnknown

NRW (Wales) · UKGB110064048440

Why this score · for atlantic salmon
  • Temperature030% weight
  • Flow6025% weight
  • Clarity9520% weight
  • Feeding Time8515% weight
  • Pressure8510% weight
Directions
Seasons & zones
  • Salmon1 April → 17 October
  • Sea trout3 March → 17 October
  • Trout3 March → 30 September

Sea trout: Variable seasonal (2026) — NRW At Risk classification. Compact spate river with poor water quality stretches and acid pressure. Honest small-river sport on the right pulse; nothing to fish in flat low summer water.

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