- Ecology: Moderate
- Chemical: Unknown
EA (England) · UKGB104028052390
Water temperature for Brown Trout
Warm — slow20°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Olives April through May; Mayfly late May where it shows; sedges through summer; small dark flies into October. Peak District weather changes fast.
Where
Upper Derwent above Bamford is tight pocket water; the middle river through Hathersage and Calver runs through productive trout water.
Method
Upstream dry to risers when olives or sedges are off; North Country spider on the swing in cooler water — Snipe and Purple, Partridge and Orange, Waterhen Bloa. Move upstream slowly, fish each lie properly.
Kit
9 ft #4 — Yorkshire freestone default. Floating line, 9 to 12 ft leader to 4 to 5 lb fluoro. Studded boots for slick stones.
Why this works
Water at 20.3°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 5pm
Hatch predictions
Today's headline hatch shown — see all 10 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 3 guilds 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 · 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
2
1
Grayling seasonSeason
2
2
1
1
2
2
2
2
2
2
Daddy Long LegsHatch
2
3
2
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
Local classics: Greenwell's Glory·Pheasant Tail Nymph
What's coming
Plan ahead
5-day outlook
Water here around 20°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
The River Derwent at Matlock Bath, Derbyshire Terrain map
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 80%
How the 26 is built — score × weight = contribution
Temperature21 × 28%5.9
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Limiting factor: Water temperature (20.3°C) is outside Brown Trout's preferred range (10–16°C)= 64
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.
Directions
Seasons & zones
- Trout 22 March → 30 September
- Grayling 16 June → 14 March
Derbyshire Derwent grayling typically follows the full statutory window on club and association water. Autumn through early winter is the prime period. Check specific club rules for methods.
Prime sport 1 September → 31 December
Related guides
Casting instructors near here
Booking & contacts
Clubs & associations
River Derwent (Derbyshire)
Water temperature for Brown Trout
Warm — slow20°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Olives April through May; Mayfly late May where it shows; sedges through summer; small dark flies into October. Peak District weather changes fast.
Where
Upper Derwent above Bamford is tight pocket water; the middle river through Hathersage and Calver runs through productive trout water.
Method
Upstream dry to risers when olives or sedges are off; North Country spider on the swing in cooler water — Snipe and Purple, Partridge and Orange, Waterhen Bloa. Move upstream slowly, fish each lie properly.
Kit
9 ft #4 — Yorkshire freestone default. Floating line, 9 to 12 ft leader to 4 to 5 lb fluoro. Studded boots for slick stones.
Why this works
Water at 20.3°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 5pm
Hatch predictions
Today's headline hatch shown — see all 10 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
Top nymph shown — see all 3 guilds 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 · 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
2
1
Grayling seasonSeason
2
2
1
1
2
2
2
2
2
2
Daddy Long LegsHatch
2
3
2
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
Local classics: Greenwell's Glory·Pheasant Tail Nymph
What's coming
Plan ahead
5-day outlook
Water here around 20°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
The River Derwent at Matlock Bath, Derbyshire Terrain map
Water quality (WFD)
- Ecology: Moderate
- Chemical: Unknown
EA (England) · UKGB104028052390
The full read · show the working · for Brown Trout · confidence 80%
How the 26 is built — score × weight = contribution
Temperature21 × 28%5.9
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Limiting factor: Water temperature (20.3°C) is outside Brown Trout's preferred range (10–16°C)= 64
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.
Directions
Seasons & zones
- Trout 22 March → 30 September
- Grayling 16 June → 14 March
Derbyshire Derwent grayling typically follows the full statutory window on club and association water. Autumn through early winter is the prime period. Check specific club rules for methods.
Prime sport 1 September → 31 December
Related guides
Casting instructors near here
Booking & contacts
Clubs & associations