Water temperature for Marble Trout
Warm — slow23°C est.ideal 8–13°C
0°14°28°
How to fish it · for Marble Trout
When
Dawn and dusk are best. The RPS water around Cividale del Friuli (Ponte del Diavolo to Ponte di Loch Linder/Vernasso) has long been regarded as some of the region's best marble trout fishing, historically holding well over a hundred spawning nests in a good year. Season 29 March to 27 September; single barbless hook, one fish a day.
Where
Deep pools and undercut limestone banks through the No-Kill and RPS reaches around Cividale, and in the gorge sections downstream of Vernasso.
Method
Streamer on intermediate or sink-tip, fished slow through the deep pools; in low, clear water a size down and a longer pause pays off.
Kit
9 to 10 ft #6/7, intermediate line, 8 to 10 lb fluoro, baitfish streamers. Wet net, handle with care — the No-Kill water asks for it.
Why this works
Water at 22.8°C. This is the line where catch-and-release kills marble trout. Do not fish for them today.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 2 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
Alpine RhithrogenaHatch
2
3
3
2
Sculpin / Baitfish (Rivers)Hatch
2
3
3
3
3
3
3
3
2
March BrownHatch
2
3
2
Large StoneflyHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Marble Trout fly box
Permits & access
Permit required — see local rules.
- ETPI regional licence required
- FVG Zone B season: trout open 07:00 on 29 March to 27 September, catch-and-release extension to 31 October
- Marble trout minimum size follows the FVG regional default of 50cm in this collegio (Collegio 13 Cividale) — no local 35cm exception found for the Natisone
- Grayling minimum size 60cm, one retained specimen per angler per calendar year region-wide
- Single barbless hook mandatory on the Cividale No-Kill and RPS water.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Probably above the Marble Trout safety line — these are likely cooler, but carry a thermometer.
Gallery · 1
Terrain map
The full read · show the working · for Marble Trout · confidence 90%
How the 10 is built — score × weight = contribution
Temperature6 × 28%1.7
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time65 × 13%8.5
Pressure80 × 7%5.6
Insect activity58 × 12%7.0
Limiting factor: Water temperature (22.8°C) is outside Marble Trout's preferred range (8–13°C)= 53
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 8–13 °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 2026-03-29 → 2026-09-27
- Grayling 2026-06-01 → 2026-09-27
Rules are set at province or association level — check locally.
- Marble trout 2026-03-29 → 2026-09-27
Related guides
Booking & contacts
Natisone
Water temperature for Marble Trout
Warm — slow23°C est.ideal 8–13°C
0°14°28°
How to fish it · for Marble Trout
When
Dawn and dusk are best. The RPS water around Cividale del Friuli (Ponte del Diavolo to Ponte di Loch Linder/Vernasso) has long been regarded as some of the region's best marble trout fishing, historically holding well over a hundred spawning nests in a good year. Season 29 March to 27 September; single barbless hook, one fish a day.
Where
Deep pools and undercut limestone banks through the No-Kill and RPS reaches around Cividale, and in the gorge sections downstream of Vernasso.
Method
Streamer on intermediate or sink-tip, fished slow through the deep pools; in low, clear water a size down and a longer pause pays off.
Kit
9 to 10 ft #6/7, intermediate line, 8 to 10 lb fluoro, baitfish streamers. Wet net, handle with care — the No-Kill water asks for it.
Why this works
Water at 22.8°C. This is the line where catch-and-release kills marble trout. Do not fish for them today.
Hatch timeline · todayQuiet day
Hatch predictions
Today's headline hatch shown — see all 2 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
Alpine RhithrogenaHatch
2
3
3
2
Sculpin / Baitfish (Rivers)Hatch
2
3
3
3
3
3
3
3
2
March BrownHatch
2
3
2
Large StoneflyHatch
2
3
2
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Marble Trout fly box
Permits & access
Permit required — see local rules.
- ETPI regional licence required
- FVG Zone B season: trout open 07:00 on 29 March to 27 September, catch-and-release extension to 31 October
- Marble trout minimum size follows the FVG regional default of 50cm in this collegio (Collegio 13 Cividale) — no local 35cm exception found for the Natisone
- Grayling minimum size 60cm, one retained specimen per angler per calendar year region-wide
- Single barbless hook mandatory on the Cividale No-Kill and RPS water.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Probably above the Marble Trout safety line — these are likely cooler, but carry a thermometer.
Gallery · 1
Terrain map
The full read · show the working · for Marble Trout · confidence 90%
How the 10 is built — score × weight = contribution
Temperature6 × 28%1.7
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time65 × 13%8.5
Pressure80 × 7%5.6
Insect activity58 × 12%7.0
Limiting factor: Water temperature (22.8°C) is outside Marble Trout's preferred range (8–13°C)= 53
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 8–13 °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 2026-03-29 → 2026-09-27
- Grayling 2026-06-01 → 2026-09-27
Rules are set at province or association level — check locally.
- Marble trout 2026-03-29 → 2026-09-27
Related guides
Booking & contacts