A southeasterly has held for 15 hours, running colder than the water (10°C air against 13°C water). The end it blows into is taking that chilled surface water, so try the sheltered south-eastern end instead — off the back of the wind, where the undertow returns food along the bottom. That chill sits in the top of the water, though, and the bed is slower to feel it — on a bottom bait it is the undertow, not the temperature, that puts you at this end. Treat it as a tiebreaker between good swims rather than an override — features and angling pressure usually count for more.
Start with Cormorant (10-12) — on the bob / top dropper. Early in the day, try buzzers on a slow figure-of-eight or a booby on a fast-sink line near the bottom. Rainbows respond to more active retrieves — try short strips between pauses.
If the main plan stalls, drop to a size 14–16 midge — switch to a washing-line or suspender rig and change drift line before you change food group.
Keep an eye on changing conditions — wind shifts and cloud breaks can trigger short feeding spells.
Good ripple suits both bank and boat. Bank: work inflows, dam walls, and points. Boat: broadside drift covering wind lanes.
Hatch predictions
Top nymph shown — see all 3 guilds as a supporter.
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Hatch predictions
Top prey shown — see all 5 as a supporter.
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Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Boat-friendly, competition-influenced, often wind-driven, with strong top-of-water periods but also classic deep searching and washing-line phases.
A good match for Llyn Brenig — most conditions are close to what it fishes best in.
919-acre upland reservoir on the Hiraethog moors above Cerrigydrudion. One of Wales's premier stillwater trout fisheries — boat and bank. Stocked with brown and rainbow trout, with wild browns breeding in feeder streams. Competition venue. Excellent buzzer, Diawl Bach and damsel fishing. Visitor centre and boats from sailing club end.
NRW WFD Cycle 3 (lake) — Llyn Brenig: Moderate ecological status. Re-tagged 2026-06-18 from a feeder-river reach to the reservoir's own lake waterbody. Source: NRW DataMapWales WFD Cycle 3 classification layer.
NRW (Wales) · GB31133923
919-acre upland reservoir on the Hiraethog moors above Cerrigydrudion.
A southeasterly has held for 15 hours, running colder than the water (10°C air against 13°C water). The end it blows into is taking that chilled surface water, so try the sheltered south-eastern end instead — off the back of the wind, where the undertow returns food along the bottom. That chill sits in the top of the water, though, and the bed is slower to feel it — on a bottom bait it is the undertow, not the temperature, that puts you at this end. Treat it as a tiebreaker between good swims rather than an override — features and angling pressure usually count for more.
Start with Cormorant (10-12) — on the bob / top dropper. Early in the day, try buzzers on a slow figure-of-eight or a booby on a fast-sink line near the bottom. Rainbows respond to more active retrieves — try short strips between pauses.
If the main plan stalls, drop to a size 14–16 midge — switch to a washing-line or suspender rig and change drift line before you change food group.
Keep an eye on changing conditions — wind shifts and cloud breaks can trigger short feeding spells.
Good ripple suits both bank and boat. Bank: work inflows, dam walls, and points. Boat: broadside drift covering wind lanes.
Hatch predictions
Top nymph shown — see all 3 guilds as a supporter.
Start free trial14-day free trial. Cancel anytime.
Hatch predictions
Top prey shown — see all 5 as a supporter.
Start free trial14-day free trial. Cancel anytime.
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Boat-friendly, competition-influenced, often wind-driven, with strong top-of-water periods but also classic deep searching and washing-line phases.
A good match for Llyn Brenig — most conditions are close to what it fishes best in.
919-acre upland reservoir on the Hiraethog moors above Cerrigydrudion. One of Wales's premier stillwater trout fisheries — boat and bank. Stocked with brown and rainbow trout, with wild browns breeding in feeder streams. Competition venue. Excellent buzzer, Diawl Bach and damsel fishing. Visitor centre and boats from sailing club end.
NRW WFD Cycle 3 (lake) — Llyn Brenig: Moderate ecological status. Re-tagged 2026-06-18 from a feeder-river reach to the reservoir's own lake waterbody. Source: NRW DataMapWales WFD Cycle 3 classification layer.
NRW (Wales) · GB31133923
