Spate · Mixed · South Wales / Cardiff

River Ely

The River Ely flowing through green banks near Cardiff, Wales
Poor · Brown Trout
CDC Emerger · 16-18
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.
90% confidence
What moved it
  • Level0.18 mLast reading 5h ago
  • Water temp23.0°C
  • ClarityClear
Today's fly
CDC Emerger
CDC Emerger16-18
Upstream dry, in the film
Conditions on the water
Live gauge
Level
Steady
0.18 m
Last reading 5h ago
Water temp23.0°C
ClarityClear
Weather24°C
WindW 24 km/h
Pressure1018 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

Live readings only. Trends shown where the gauge supports them.

Water temperature for Brown Trout
Warm — slow
23.0°Cideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the open trout season. Spring olives and summer sedges through the middle reaches; modest fly life compared to the upper Taff.
Where
Upper and middle Ely above the Cardiff suburbs.
Method
Upstream dry to risers through summer; dry-dropper through the runs. Where the river slows through farmland, longer leaders and lighter tippet earn the takes. Spider patterns on the swing when olives are off the water.
Kit
9 ft #4. Floating line, 12 ft leader to 4 to 5 lb fluoro. Wading is usually easy on the lower reaches — the upper valley is rockier.
Why this works
Water at 23°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayPeak at 6am

Hatch predictions

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Beyond the hatch · worth watchingambient prey

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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 · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
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.

Ranked for today
Brown Trout fly box
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Water here at 23.0°C — too warm to fish Brown Trout safely. These are cooler.
Bargoed Park
18 km
~23°C
Brown trout · Rainbow trout
Gallery · 2
  1. The River Ely flowing through green banks near Cardiff, Wales
    The River Ely, Cardiff, Wales
  2. Terrain map of the venue
    Terrain map
Water quality (WFD)
  • Ecology: Poor
  • Chemical: Unknown
What this classification means

NRW WFD Cycle 3 — Ely (conf Nant Clun to Ely, Cardiff): Poor ecological status. Corrected 2026-06-18 from a Nant-Dowlais tributary tag (was recorded Moderate). Source: NRW DataMapWales WFD Cycle 3 classification layer.

EA (England) · GB109057027260

The full read · show the working · for Brown Trout · confidence 90%
How the 4 is built — score × weight = contribution
Temperature2 × 28%0.6
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity50 × 12%6.0
Limiting factor: Water temperature (23°C) is outside Brown Trout's preferred range (10–16°C)= 55
Can you trust it?
Water temperaturelive gauge readinggauge
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.
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Sea trout 3 March → 17 October
  • Trout 3 March → 30 September

Sea trout: Variable seasonal (2026) — Small urban river; sewin work up on autumn lifts in very modest numbers. The Ely is the smallest of the three Cardiff-area rivers and the least established as a migratory fishery. All-Wales At Risk picture applies.

Related guides
Yorkshire & SpidersNorth Country methodsEuro Nymphingsubsurface methods
Casting instructors near here
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