- Ecology: Good
- Chemical: Unknown
WFD classification · HRCSRN0481_001
Water temperature for Brown Trout
Warm — slow20°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 19.9°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 6am
Hatch predictions
Today's headline hatch shown — see all 4 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
See the full sub-surface read 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
ModelledModerate confidence
Modelled from regional ecology — no survey or occurrence data for this water 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
1
Grayling seasonSeason
1
2
2
2
2
1
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
Top
12-16 · Pattern
Proven pattern for this period
Permits & access
Permit required — see local rules.
- Croatian fishing licence plus local permit
- Risnjak park section is catch-and-release, fly only, single barbless hook, no boats, and no night fishing
- Park entrance also applies.
What's coming
Plan ahead
5-day outlook
Water here around 20°C. Nothing cooler within range — carry a thermometer.
Gallery · 1
IMG 20180713 163857(fixed)
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature26 × 28%7.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Conditions total= 63
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
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
- Trout 16 May → 30 September
- Grayling 16 May → 15 October
Conflicting sources for Kupa grayling season: Risnjak National Park (upper Kupa, C&R) lists grayling 16 May – 15 October; Kupa Fly Fishing operator lists 1 April – 15 October. Use the stricter May window until the specific beat/concession confirms otherwise. Croatian national rule: one rod, artificial fly or lure only in permanent grayling habitats.
Prime sport 1 August → 15 October
- 16 May → 15 Oct · Artificial fly or artificial lure
- Hucho 1 October → 28 February
Related guides
Booking & contacts
Kupa (Upper / Risnjak NP)
Water temperature for Brown Trout
Warm — slow20°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 19.9°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 6am
Hatch predictions
Today's headline hatch shown — see all 4 active hatches hour by hour with Pro.
Start free trial14-day free trial. Cancel anytime.
Sub-surface · on the nymphunder the surface
Hatch predictions
See the full sub-surface read 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
ModelledModerate confidence
Modelled from regional ecology — no survey or occurrence data for this water 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
1
Grayling seasonSeason
1
2
2
2
2
1
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Brown Trout fly box
Top
12-16 · Pattern
Proven pattern for this period
Permits & access
Permit required — see local rules.
- Croatian fishing licence plus local permit
- Risnjak park section is catch-and-release, fly only, single barbless hook, no boats, and no night fishing
- Park entrance also applies.
What's coming
Plan ahead
5-day outlook
Water here around 20°C. Nothing cooler within range — carry a thermometer.
Gallery · 1
IMG 20180713 163857(fixed)
Water quality (WFD)
- Ecology: Good
- Chemical: Unknown
WFD classification · HRCSRN0481_001
The full read · show the working · for Brown Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature26 × 28%7.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Conditions total= 63
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
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
- Trout 16 May → 30 September
- Grayling 16 May → 15 October
Conflicting sources for Kupa grayling season: Risnjak National Park (upper Kupa, C&R) lists grayling 16 May – 15 October; Kupa Fly Fishing operator lists 1 April – 15 October. Use the stricter May window until the specific beat/concession confirms otherwise. Croatian national rule: one rod, artificial fly or lure only in permanent grayling habitats.
Prime sport 1 August → 15 October
- 16 May → 15 Oct · Artificial fly or artificial lure
- Hucho 1 October → 28 February
Related guides
Booking & contacts