Upland Natural Lake · Slate · Gwynedd / Snowdonia, GB-WLS

Llynnau Mymbyr

Panoramic view across the twin lakes of Llynnau Mymbyr toward Moel Siabod and Snowdon in Eryri National Park, Wales

Twin llyns in the Nant Gwynant valley below Snowdon.

Fair · Trout
Diawl Bach · 12-14
Fairlive now
Good drifting conditions on Llynnau Mymbyr
Glassy and bright — hard work without a breeze. Hard work without breeze. Look for the dimples.
55% confidence
What moved it
  • WindE 5 km/hCalm
Today's fly
Diawl Bach
Diawl Bach12-14
Washing-line, sub-surface
Conditions on the water
Live gauge
Wind
Calm
E 5 km/h
N
E
from the east
WaveFlat calm
Water temp
Air temp9°C
CloudOvercast
Pressure1021 hPa
Rain · recent0.0 mm

Some readings unavailable — check directly before fishing.

How to fish it · for Trout
When
May to September
Where
With limited drift, anchor or fish static from sheltered positions. Work a bushy searching pattern on the bob and drop a contrasting nymph on the point. In the calm, a single dry fly or a slowly-fished nymph tends to out-fish an active retrieve.
The plan
Plan A

With limited drift, anchor or fish static from sheltered positions. Work a bushy searching pattern on the bob and drop a contrasting nymph on the point. In the calm, a single dry fly or a slowly-fished nymph tends to out-fish an active retrieve.

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

Evening tends to be the best period in summer — stay late if you can for a sedge or spinner fall.

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 2 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
54%
Cloud70%
Wind65%
Temp25%

A reasonable day here, though temperature isn't quite in the sweet spot.

Other water nearby · 5
Gallery · 2
  1. Panoramic view across the twin lakes of Llynnau Mymbyr toward Moel Siabod and Snowdon in Eryri National Park, Wales
    Llynnau Mymbyr looking toward Moel Siabod and Snowdon, Eryri
  2. Terrain map of the venue
    Terrain map
About this water

Twin llyns in the Nant Gwynant valley below Snowdon. Wild brown trout with dramatic mountain backdrop — perhaps Wales's most photographed fishing location. Capel Curig area. Small wild trout respond to traditional wet flies, dabblers and terrestrials. Day tickets from Plas y Brenin.

  • Lake
  • Slate
Why this score
  • Lake Olive 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