Chalk Stream · Limestone · Gloucestershire (Cotswolds)

River Coln

A clear chalk stream, the River Coln, with visible gravel bed and weed, flowing under an arched footbridge lined with willows.

The Coln runs through some of the prettiest Cotswold villages — Withington, Fosse Bridge, Bibury, Fairford — to join the Thames near Lechlade.

Marginal · Brown Trout
CDC F-Fly · 18-20
Marginallive now
Slow going — pick your moments
River temperature is the limiting factor today, not the flow. Fish dawn or dusk if you go at all, and handle everything with extra care.
80% confidence
What moved it
  • Level0.43 mLast reading 8h ago
  • Water temp20.4°C
  • ClarityClear
Today's fly
CDC F-Fly
CDC F-Fly18-20
Upstream dry, on top
Conditions on the water
Live gauge
Level
Steady
0.43 m
Last reading 8h ago
Water temp20.4°C
ClarityClear
Weather32°C
WindSE 13 km/h
Pressure1021 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for Brown Trout
Warm — slow
20°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Water at 20.4°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · todayPeak at 6pm

Hatch predictions

Today's headline hatch shown — see all 11 active hatches hour by hour with Pro.

Start free trial

14-day free trial. Cancel anytime.

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 2 guilds with Pro.

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 with Pro.

Start free trial

14-day free trial. Cancel anytime.

Evidence
Survey-backed · regionalHigh confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

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
1
Brown SedgeHatch
2
3
2
Freshwater ShrimpHatch
2
3
3
3
3
3
3
3
3
3
3
2
Blue Winged OliveHatch
2
3
3
3
3
2
Mayfly (Green Drake)Hatch
2
2

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

Ranked for today
Brown Trout fly box

The heartland of English dry fly fishing. Upstream dry fly and emerger presentation dominates. Nymphing restricted or discouraged on many beats. Gin-clear alkaline water, prolific weed growth, educated wild brown trout. Precise imitation and delicate presentation are paramount.

Permits & access
Permit required — see local rules.
  • Bibury Trout Farm day tickets cover the famous beat
  • Other beats syndicate.
What's coming
Plan ahead
5-day outlook
Water here around 20°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. A clear chalk stream, the River Coln, with visible gravel bed and weed, flowing under an arched footbridge lined with willows.
    River Coln, Bibury
  2. Terrain map of the venue
    Terrain map
About this water

The Coln runs through some of the prettiest Cotswold villages — Withington, Fosse Bridge, Bibury, Fairford — to join the Thames near Lechlade. The Bibury beat is famously associated with Bibury Trout Farm and the village's chalk-stream identity. Mixed wild and stocked brown trout, grayling on some beats. Mostly private but Bibury area accessible via the trout farm structure.

  • Limestone
The full read · show the working · for Brown Trout · confidence 80%
How the 25 is built — score × weight = contribution
Temperature20 × 28%5.6
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity63 × 12%7.6
Limiting factor: Water temperature (20.4°C) is outside Brown Trout's preferred range (10–16°C)= 61
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Cooler water — back toward the 10–16 °C ideal band — would lift the score and ease welfare.
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 April → 30 September
Related guides
Chalkstream Playbookchalk stream tacticsGrayling Playbookgrayling tacticsTrout Near Londonaccess guide
Casting instructors near here
Booking & contacts