Spate · Carboniferous Coal Measures · Wales / South Wales (Aberdare)

Afon Cynon

Afon Cynon venue image
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The Cynon at Aberdare — half a mile of mostly double-bank fishing, medium to small river with some surprisingly deep pools.

Poor · Brown Trout
Pheasant Tail Nymph · 14-16
Poorlive now
Not the day for it
River temperature is the limiting factor today, not the flow. This is not the day to push it. Check the thermal advice above before you head out.
80% confidence
What moved it
  • LevelDry recentlyNo gauge reading
  • Water temp21.6°C
  • ClarityClear
Today’s fly
Pheasant Tail Nymph
Pheasant Tail Nymph14-16
Upstream, sub-surface
Conditions on the water
Estimate
Level
Dry recently
No gauge reading
Water temp21.6°C
ClarityClear
Weather25°C
WindN 8 km/h
Pressure1018 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

Water temperature for brown trout
Warm — slow
22°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.
Why this works
⚠️ Water at 21.6°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots. Otherwise very poor — water clarity is in the right range.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 3 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
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.

Ranked for today
Brown Trout fly box
Beats · 1
Ynysllwyd (Aberdare AA) — Wild Stream day ticketAccess varies
Half a mile of mostly double-bank wild brown trout fishing on the Cynon at Aberdare.
What's coming
Plan ahead
5-day outlook
Water here around 22°C. Nothing cooler within range — carry a thermometer.
Gallery · 1
  1. Terrain map of the venue
    Terrain map
About this water

The Cynon at Aberdare — half a mile of mostly double-bank fishing, medium to small river with some surprisingly deep pools. Chest waders recommended. Wild brown trout in post-industrial water that has recovered from worse than most rivers ever see; a useful reminder that South Wales has real trout fishing if you know where to look. Wild Stream Passport beat — eleven quid a day or part of the Wild Stream season permit.

  • Carboniferous coal measures
The full read · show the working · for brown trout · confidence 80%
How the 17 is built — score × weight = contribution
Temperature9 × 28%2.5
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity54 × 12%6.5
Limiting factor: Water temperature (21.6°C) is outside Brown Trout's preferred range (10–16°C)= 54
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
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.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout3 March → 30 September
Related guides
Yorkshire & SpidersNorth Country methodsEuro Nymphingsubsurface methods
Booking & contacts