- Ecology: Good
- Chemical: Unknown
NRW (Wales) · UKGB110060036284
Water temperature for Brown Trout
Warm — slow18°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
Good — water clarity is working for you, but time of day is the limiting factor today.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 7 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 2 with Pro.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalModerate confidence
Backed by regional invertebrate surveys; no sampling on this exact reach yet.
Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Salmon runRun
1
2
2
2
2
2
1
Trout seasonSeason
1
2
2
2
2
2
1
Daddy Long LegsHatch
2
3
2
March BrownHatch
2
3
2
GrannomHatch
2
2
Large StoneflyHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
14-18 · Pattern
Upstream dry, on top
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
River Taf — image via Wikipedia (River Taf) Terrain map
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 75%
How the 69 is built — score × weight = contribution
Temperature62 × 28%17.4
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity49 × 12%5.9
Conditions total= 69
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
Seasons & zones
- Salmon 1 April → 17 October
- Trout 3 March → 30 September
Sea trout: Variable seasonal (2026) — NRW At Risk classification. Compact South Wales river with sewin runs from June. Stocks are marginal under current At Risk rating — night fishing in warm summer conditions is the productive window when water is right.
Salmon: Negligible (2026) — NRW / EA 2024 Salmon Stocks Assessment classifies this Welsh principal salmon river 'at risk' — egg deposition below Conservation Limit. All Wales byelaws (in force 2020-2030) make catch & release mandatory. Conservation priority; not a salmon fishing destination. The Taf carries small numbers of salmon; classified at risk.
Related guides
Casting instructors near here
Booking & contacts
Clubs & associations
River Taf
Water temperature for Brown Trout
Warm — slow18°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
Good — water clarity is working for you, but time of day is the limiting factor today.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 7 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey
Hatch predictions
Top prey shown — see all 2 with Pro.
Start free trial14-day free trial. Cancel anytime.
Evidence
Survey-backed · regionalModerate confidence
Backed by regional invertebrate surveys; no sampling on this exact reach yet.
Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Salmon runRun
1
2
2
2
2
2
1
Trout seasonSeason
1
2
2
2
2
2
1
Daddy Long LegsHatch
2
3
2
March BrownHatch
2
3
2
GrannomHatch
2
2
Large StoneflyHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
14-18 · Pattern
Upstream dry, on top
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 2
River Taf — image via Wikipedia (River Taf) Terrain map
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
NRW (Wales) · UKGB110060036284
The full read · show the working · for Brown Trout · confidence 75%
How the 69 is built — score × weight = contribution
Temperature62 × 28%17.4
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity49 × 12%5.9
Conditions total= 69
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
Seasons & zones
- Salmon 1 April → 17 October
- Trout 3 March → 30 September
Sea trout: Variable seasonal (2026) — NRW At Risk classification. Compact South Wales river with sewin runs from June. Stocks are marginal under current At Risk rating — night fishing in warm summer conditions is the productive window when water is right.
Salmon: Negligible (2026) — NRW / EA 2024 Salmon Stocks Assessment classifies this Welsh principal salmon river 'at risk' — egg deposition below Conservation Limit. All Wales byelaws (in force 2020-2030) make catch & release mandatory. Conservation priority; not a salmon fishing destination. The Taf carries small numbers of salmon; classified at risk.
Related guides
Casting instructors near here
Booking & contacts
Clubs & associations