Water temperature for Brown Trout
Warm — slow23°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 22.7°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day
Hatch predictions
See the full hour-by-hour hatch timeline 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
March BrownHatch
2
3
2
GrannomHatch
2
2
Large StoneflyHatch
2
3
2
Yellow SallyHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
Permits & access
Permit required — see local rules.
- Aragón fishing licence required
- Named cotos, social cotos, and special high-mountain sections can have different dates, permit allocations, and method rules, so check the current Aragón plan for the exact beat.
What's coming
Plan ahead
5-day outlook
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2

Río Gállego, Huesca, España, 2023-01-05, DD 12-16 PAN Terrain map
The full read · show the working · for Brown Trout · confidence 90%
How the 6 is built — score × weight = contribution
Temperature3 × 28%0.8
Flow80 × 22%17.6
Clarity15 × 18%2.7
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity38 × 12%4.6
Limiting factor: Water temperature (22.7°C) is outside Brown Trout's preferred range (10–16°C)= 39
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.
A drop and clear would lift the flow and clarity scores.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout check named Aragón coto or free section → check named Aragón coto or free section
Related guides
Booking & contacts
Río Gállego

Water temperature for Brown Trout
Warm — slow23°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 22.7°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day
Hatch predictions
See the full hour-by-hour hatch timeline 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
March BrownHatch
2
3
2
GrannomHatch
2
2
Large StoneflyHatch
2
3
2
Yellow SallyHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
Permits & access
Permit required — see local rules.
- Aragón fishing licence required
- Named cotos, social cotos, and special high-mountain sections can have different dates, permit allocations, and method rules, so check the current Aragón plan for the exact beat.
What's coming
Plan ahead
5-day outlook
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2

Río Gállego, Huesca, España, 2023-01-05, DD 12-16 PAN Terrain map
The full read · show the working · for Brown Trout · confidence 90%
How the 6 is built — score × weight = contribution
Temperature3 × 28%0.8
Flow80 × 22%17.6
Clarity15 × 18%2.7
Feeding Time55 × 13%7.2
Pressure80 × 7%5.6
Insect activity38 × 12%4.6
Limiting factor: Water temperature (22.7°C) is outside Brown Trout's preferred range (10–16°C)= 39
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.
A drop and clear would lift the flow and clarity scores.
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
- Trout check named Aragón coto or free section → check named Aragón coto or free section
Related guides
Booking & contacts