Stillwater · Mixed · Renfrewshire

Castle Semple Loch

Castle Semple Loch terrain map

A broad, shallow loch at the centre of Clyde Muirshiel Regional Park, 25 km south-west of Glasgow near Lochwinnoch.

Fair · Rainbow
Marabou Damsel · 8-12
Fairlive now
Good drifting conditions on Castle Semple Loch
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.
57% confidence

Castle Semple Loch is often best in spring through autumn.

What moved it
  • WindSW 12 km/hGentle breeze
Today's fly
MD
Marabou Damsel8-12
Retrieve, sub-surface
Conditions on the water
Live gauge
Wind
Gentle breeze
SW 12 km/h
N
SW
from the south-west
Wave20 cm ripple
Water temp—
Air temp23°C
CloudOvercast
Pressure1020 hPa
Rain · recent0.0 mm

Some readings unavailable — check directly before fishing.

How to fish it · for Rainbow
When
The buzzers are on. Daddy longlegs may also come into play as the day warms. Drift conditions look good — cover the wind lanes. The breeze will be blowing terrestrial insects onto the water — check the wind lanes and downwind margins for rising fish.
Where
Set up a broadside drift and cover the water systematically. Work Black Pennell on the bob, Ke-He on the middle dropper, and Marabou Damsel on the point.
The plan
Plan A

Set up a broadside drift and cover the water systematically. Work Black Pennell on the bob, Ke-He on the middle dropper, and Marabou Damsel 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

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

Boat — drift

A gentle ripple is ideal for drifting — broadside drift covering the wind lanes should be productive.

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
2
1
Daphnia SwarmHatch
2
3
3
3
2
Daddy Long LegsHatch
2
3
2
Lake OliveHatch
2
3
3
3
3
3
2
Silverhorns & LonghornsHatch
1
2
2
2
1

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

Ranked for today
Rainbow fly box
What's coming
Plan ahead
5-day outlook
Condition match
49%
Cloud50%
Wind65%
Temp25%

Conditions are away from Castle Semple Loch's sweet spot — it usually fishes best in ripple wind with cloud skies.

Other water nearby · 5
New Haylie Trout Fishery
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Rainbow trout · Brown trout
Craufurdland Fishery
19 km
Rainbow trout
Carman Fishery
20 km
Rainbow trout
River Kelvin
21 km
Brown trout
Carbeth Fishery
22 km
Rainbow trout
About this water

A broad, shallow loch at the centre of Clyde Muirshiel Regional Park, 25 km south-west of Glasgow near Lochwinnoch. Castle Semple is shared water — watersports, paddleboards, a visitor centre, the occasional RSPB scope pointed at the far shore — and the fishing sits inside that broader use. Managed by the local angling club. Stocked rainbow and brown trout in the spring, with a wild brown component that holds on through the summer. It will never feel like a wild hill loch, but for an angler who wants a couple of hours at the end of a working day and a short drive home, it does the job.

  • Loch
  • Mixed
Why this score
  • Buzzers are in their seasonal window, boosting the chance of targeted feeding.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 15 March → 6 October
Related guides
Scotland Playbookloch & river fishingSmall Stillwater Playbookstillwater tacticsThermal Layers & Troutreading depth and temperature
Casting instructors near here
Booking & contacts