Spate · Peat · Outer Hebrides / Lewis

Grimersta River & Loch System

Loch Grimersta on the Isle of Lewis, a chain loch of the Grimersta salmon fishery system, with hills in the distance.

Scotland's most famous island salmon fishery — a short, fast spate river draining a chain of lochs on the west side of Lewis.

Good · Atlantic Salmon
Stoat's Tail · 8-12 double
Goodlive now
A good day — worth the effort
River high but settled. Water still carrying colour. Heavier flies, settled lies.
85% confidence
What moved it
  • LevelProxyvia River Ewe / Loch Maree
  • Water temp16.2°C
  • ClaritySlightly coloured
Today's fly
Stoat's Tail
Stoat's Tail8-12 double
Regional salmon default — river-specific evidence is thin.
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via River Ewe / Loch Maree
Water temp16.2°C
ClaritySlightly coloured
Weather15°C
WindW 27 km/h
Pressure1016 hPa
Rain · recent1.4 mm
Rain · ahead5.8 mm

No gauge on this water — conditions are inferred from River Ewe / Loch Maree. The trend transfers, the absolute level does not.

Water temperature for Atlantic Salmon
Warm — slow
16°C est.ideal 10–14°C
0°14°28°
How to fish it · for Atlantic Salmon
When
All day — lough fishing is best in a good wave. Early morning and evening can produce in calm conditions.
Where
Work the drift lanes from the upwind shore across the productive zones. Cover bay edges, underwater reefs, and any areas where the bottom shoals.
Method
Fish a sensible line-and-fly combination for the height and pace of water.
Kit
10 ft #7/8 single-hander, floating line, 10–12 lb fluoro leader. Boat seat and waterproofs for the drift.
Why this works
Good — water clarity is right today, though water temperature could be better.
Hatch timeline · todayPeak at 6pm

Hatch predictions

Today's headline hatch shown — see all 12 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

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Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Salmon runRun
1
2
2
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
Atlantic Salmon fly box

Rougher, darker and more traditional. Stronger weighting on dark wets, bushy bob flies and commotion-making patterns.

Permits & access
Permit required — see local rules.
  • Premium managed fishery — advance booking through Grimersta Estate
  • Very limited availability
  • Fly only.
What's coming
Plan ahead
5-day outlook
Other water nearby · 3
Loch Roag System
5.0 km
Brown trout · Salmon · Sea trout
Loch Morsgail
9.0 km
67
Brown trout · Salmon · Sea trout
Loch Langavat (Lewis)
15 km
Brown trout · Char · Salmon
Gallery · 2
  1. Loch Grimersta on the Isle of Lewis, a chain loch of the Grimersta salmon fishery system, with hills in the distance.
    Loch Griomarstadh (Loch Grimersta), part of the Grimersta river and loch system, Isle of Lewis.
  2. Terrain map of the venue
    Terrain map
About this water

Scotland's most famous island salmon fishery — a short, fast spate river draining a chain of lochs on the west side of Lewis. The Grimersta is extraordinary: in a good spate it can produce salmon catches that rival any river in Scotland, despite being barely a mile long. The system's magic lies in its chain of lochs which act as holding pools, and the short river which fish run through in hours rather than days after rain. Sea trout also run the system in good numbers. The fishing is managed as a premium let and commands high prices, but when it fires after a summer spate, there is nothing else quite like it in Scottish salmon fishing. Peat-stained moorland water defines this river. Atlantic salmon stocks are Category 3 (declining) — all salmon must be released.

Sea trout here

Summer-autumn runs, seasonal patterns vary by region

  • Loch
  • Peat
Why this score · for Atlantic Salmon
  • Temperature5330% weight
  • Flow6025% weight
  • Clarity8520% weight
  • Feeding Time8015% weight
  • Pressure8510% weight
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Salmon 11 February → 31 October

Sea trout: Variable seasonal (2026) — Grimersta — the most celebrated sea trout system in the British Isles historically. Lewis loch chain with a legendary record for very large sea trout. Stocks have collapsed under sea-lice pressure from west-coast salmon farms; catches are a fraction of their 1970s–80s peak. Still worth fishing carefully when conditions align, but the days of double-figure fish in numbers are gone. Catch-and-release mandatory under contemporary estate management.

Related guides
Scotland Playbookloch & river fishingThermal Layers & Troutreading depth and temperatureAtlantic Salmonsalmon tactics
Booking & contacts