Rules at a glance
- Free fishing
- Fly only
Water temperature for Brown Trout
Warm — slow20°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the FVG trout season. The Natisone runs gin-clear for a limestone river, so approach and light matter more here than almost anywhere else in the region.
Where
Pool tails and current seams through the gorges below Pulfero and San Pietro al Natisone, where the valley narrows.
Method
Long, fine leaders and careful wading — the clarity that makes this river beautiful also makes it easy to put fish down. Upstream nymph and dry-dropper both work if you stay unseen.
Kit
9 to 10 ft #4, floating line, 12 ft leader to 4 to 5 lb fluoro, fined down further in low water.
Why this works
Water at 20°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Likely species
Mayflies
Mayflies- Blue-winged oliveMost likely#16–18 · DunDuns are up; a sherry spinner fall may follow.
- Iron BlueAlso possible#16–18 · DunCold, grey day — the dun sits long. Good dry-fly water.
- Large dark oliveAlso possible#14–16 · EmergerDead-drift the emerger — it's sitting in the film.
- Anglers curse mayfliesAlso possibleLower confidence#20–22 · SpinnerGo tiny: 20-22 spent spinner, single fly, long tippet.
Caddisflies
Caddisflies- Net-spinning caddis (S. Europe)Most likelyLower confidence#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
- Satin sedgeAlso possibleLower confidence#12–14 · Egg-layingSkitter it at dusk — this one's fished, not dead-drifted.
- GrannomAlso possible#14–16 · PupaPupa first, then dries as the adults come off.
Hatch timeline · todayPeak at 6pm
Hatch predictions
Today's headline hatch shown — see all 6 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 2 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.
Through the year
0–3 scale · August 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
Brown Trout fly box
12-16 · Pattern
Upstream dry, on top
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
Water here around 20°C. Nothing cooler within range — carry a thermometer.
The full read · show the working · for Brown Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature25 × 28%7.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity66 × 12%7.9
Conditions total= 63
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
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 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 Brown Trout
Warm — slow20°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Through the FVG trout season. The Natisone runs gin-clear for a limestone river, so approach and light matter more here than almost anywhere else in the region.
Where
Pool tails and current seams through the gorges below Pulfero and San Pietro al Natisone, where the valley narrows.
Method
Long, fine leaders and careful wading — the clarity that makes this river beautiful also makes it easy to put fish down. Upstream nymph and dry-dropper both work if you stay unseen.
Kit
9 to 10 ft #4, floating line, 12 ft leader to 4 to 5 lb fluoro, fined down further in low water.
Why this works
Water at 20°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Likely species
Mayflies
- Blue-winged oliveMost likely#16–18 · DunDuns are up; a sherry spinner fall may follow.
- Iron BlueAlso possible#16–18 · DunCold, grey day — the dun sits long. Good dry-fly water.
- Large dark oliveAlso possible#14–16 · EmergerDead-drift the emerger — it's sitting in the film.
- Anglers curse mayfliesAlso possibleLower confidence#20–22 · SpinnerGo tiny: 20-22 spent spinner, single fly, long tippet.
Caddisflies
- Net-spinning caddis (S. Europe)Most likelyLower confidence#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
- Satin sedgeAlso possibleLower confidence#12–14 · Egg-layingSkitter it at dusk — this one's fished, not dead-drifted.
- GrannomAlso possible#14–16 · PupaPupa first, then dries as the adults come off.
Hatch timeline · todayPeak at 6pm
Hatch predictions
Today's headline hatch shown — see all 6 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 2 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.
Through the year
0–3 scale · August 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
Brown Trout fly box
12-16 · Pattern
Upstream dry, on top
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
Water here around 20°C. Nothing cooler within range — carry a thermometer.
The full read · show the working · for Brown Trout · confidence 80%
How the 28 is built — score × weight = contribution
Temperature25 × 28%7.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity66 × 12%7.9
Conditions total= 63
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
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 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