Upland Natural Lake · Sandstone · Powys / Brecon Beacons

Llyn Cwm Llwch

Llyn Cwm Llwch venue image

Glacial corrie llyn in the Brecon Beacons below Corn Du.

Marginal · Trout
Diawl Bach · 12-14
A patient day, if you fancy it
Water temperature is the limiting factor today, not the wave. Fish dawn or dusk if you go at all, and handle everything with extra care.
44% confidence
limited data
What moved it
  • WindW 14 km/hGentle breeze
Today's fly
Diawl Bach
Diawl Bach12-14
Washing-line, sub-surface
Conditions on the water
Live gauge
Wind
Gentle breeze
W 14 km/h
N
W
from the west
Wave20 cm ripple
Water temp
Air temp26°C
CloudBroken
Pressure1020 hPa
Rain · recent0.0 mm

Some readings unavailable — check directly before fishing.

How to fish it · for Trout
When
June to August
Where
Set up a broadside drift and cover the water systematically. Work a bushy searching pattern on the bob and drop a contrasting nymph on the point.
The plan
Plan A

Set up a broadside drift and cover the water systematically. Work a bushy searching pattern on the bob and drop a contrasting nymph on the point.

Plan B

If the main plan is not working, switch to a smaller, more imitative pattern fished slower and deeper. A change of drift angle can also make a difference.

Watch for

Watch for Sedge towards evening — this could be the best window of the day.

Bank

Bank-only venue. Fish from accessible margins, points, weed edges, and inflows.

Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 5 with Pro.

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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
Daddy Long LegsHatch
2
3
2
Murrough (Great Red Sedge)Hatch
2
3
2
Black MidgeHatch
2
3
3
3
3
3
3
3
3
3
3
2
Lake OliveHatch
1
2
2
2
2
2
1

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

Ranked for today
Trout fly box

More straightforward stocked-water behaviour than the upland competition reservoirs, with stronger early-season lure and booby bias but still good natural-fly periods.

What's coming
Plan ahead
5-day outlook
Condition match
74%
Cloud100%
Wind65%
Temp60%

A good match for Llyn Cwm Llwch — most conditions are close to what it fishes best in.

Other water nearby · 5
Gallery · 1
  1. Terrain map of the venue
    Terrain map
About this water

Glacial corrie llyn in the Brecon Beacons below Corn Du. Wild brown trout in dramatic mountain scenery. Access by 2-mile walk from Storey Arms. Classic Beacons hill llyn — small, wild fish in clear water. Traditional wet flies and dabblers.

  • Lake
  • Sandstone
Why this score
  • Cloud cover (mixed) suits the fishery well.
  • damsel is in its seasonal window, boosting the chance of targeted feeding.
Directions
Seasons & zones
  • Trout 3 March30 September
Related guides
Casting instructors near here
Booking & contacts
Clubs & associations