Rules at a glance
- Free fishing
- Fly only
- Barbless
Water temperature for Brown Trout
Ideal13°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 19.4°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- Turkey BrownMost likelyLower confidence#14–16 · DunSmall spring dun on slower glides and margins.
- Ephemera vulgata (lake mayfly)Also possibleLower confidenceNearest relative#8–10–12 · NymphLarge lake/slow-river mayfly; burrows soft sediment.
- Late March BrownAlso possibleLower confidence#12–14 · DunLate-season upland riffle dun, dusk emergence.
- Sepia DunAlso possibleLower confidenceNearest relative#12–14 · DunEarly-season dun; slow currents and lake margins.
Caddisflies
Caddisflies- Green SedgeMost likelyLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
- Net-spinning caddis (S. Europe)Also possibleLower confidenceNearest relative#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
- CapererAlso possibleLower confidence#10–12 · AdultBig autumn sedge; fish dry at last light.
- Satin sedgeAlso possibleLower confidence#12–14 · Egg-layingSkitter it at dusk — this one's fished, not dead-drifted.
Stoneflies
Stoneflies- Little Brown StoneMost likelyLower confidence#16–18 · AdultSmall dark stone nymph or adult in early spring.
- NeedleflyAlso possibleLower confidenceNearest relative#16–18 · AdultSmall slender stonefly; clean, cold headwater riffles.
Damselflies & dragonflies
Damselflies & dragonflies- Migrant HawkerMost likelyLower confidence#6–8 · NymphStrip a big hawker nymph erratically near cover.
- DamselfliesAlso possibleNearest relative#10–12 · NymphSlow-retrieve a damsel nymph along the weed edges.
Hatch timeline · todayPeak at 13 Uhr
12 Uhr(now) — Pale Watery
Stage: On emergersApproach: Emerger or dryActivity: 74%
Also:Reed Smut66%Cinnamon Sedge43%Flying Ants38%
Degree-days at peak11 food groups active
Peak activity at 13 Uhr — Pale Watery (Pale Watery, Degree-days at peak)
Sub-surface · on the nymphunder the surface
Hatch predictions
Supporters see the full sub-surface read.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 3 as a supporter.
Start free trial14-day free trial. Cancel anytime.
Evidence
Records-basedModerate confidence
Based on species-occurrence records, not local invertebrate surveys.
Through the year
0–3 scale · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Fly box · Brown Trout
Top
6-10 · Pattern
High-confidence seasonal pick
Permits & access
Permit required — see local rules.
- RD Tolmin
- Fly-only, barbless
- Upper 1km closed (breeding water).
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 3
Water here around 19°C — probably warm enough to stress Brown Trout . These are likely cooler.
Gallery · 2
Hudourniška pregrada na Beli Terrain map
The full read · show the working · for Brown Trout · confidence 80%
How the 31 is built — score × weight = contribution
Temperature19 × 28%5.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Limiting factor: Water temperature (19.4°C) is outside Brown Trout's preferred range (10–16°C)= 62
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Nadižaproxy
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.
Directions
Seasons & zones
- Trout 1 March → 30 September
- Marble trout 1 April → 31 October
Related guides
Booking & contacts
Bela (Breginj)
Water temperature for Brown Trout
Ideal13°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 19.4°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
- Turkey BrownMost likelyLower confidence#14–16 · DunSmall spring dun on slower glides and margins.
- Ephemera vulgata (lake mayfly)Also possibleLower confidenceNearest relative#8–10–12 · NymphLarge lake/slow-river mayfly; burrows soft sediment.
- Late March BrownAlso possibleLower confidence#12–14 · DunLate-season upland riffle dun, dusk emergence.
- Sepia DunAlso possibleLower confidenceNearest relative#12–14 · DunEarly-season dun; slow currents and lake margins.
Caddisflies
- Green SedgeMost likelyLower confidenceNearest relative#10–12–14–16 · NymphFree-living green caddis larva; fast stony riffles.
- Net-spinning caddis (S. Europe)Also possibleLower confidenceNearest relative#12–14–16 · PupaWidespread riffle net-spinner; evening emergence.
- CapererAlso possibleLower confidence#10–12 · AdultBig autumn sedge; fish dry at last light.
- Satin sedgeAlso possibleLower confidence#12–14 · Egg-layingSkitter it at dusk — this one's fished, not dead-drifted.
Stoneflies
- Little Brown StoneMost likelyLower confidence#16–18 · AdultSmall dark stone nymph or adult in early spring.
- NeedleflyAlso possibleLower confidenceNearest relative#16–18 · AdultSmall slender stonefly; clean, cold headwater riffles.
Damselflies & dragonflies
- Migrant HawkerMost likelyLower confidence#6–8 · NymphStrip a big hawker nymph erratically near cover.
- DamselfliesAlso possibleNearest relative#10–12 · NymphSlow-retrieve a damsel nymph along the weed edges.
Hatch timeline · todayPeak at 13 Uhr
12 Uhr(now) — Pale Watery
Stage: On emergersApproach: Emerger or dryActivity: 74%
Also:Reed Smut66%Cinnamon Sedge43%Flying Ants38%
Degree-days at peak11 food groups active
Peak activity at 13 Uhr — Pale Watery (Pale Watery, Degree-days at peak)
Sub-surface · on the nymphunder the surface
Hatch predictions
Supporters see the full sub-surface read.
Start free trial14-day free trial. Cancel anytime.
Beyond the hatch · worth watchingambient prey(1)
Hatch predictions
Top prey shown — see all 3 as a supporter.
Start free trial14-day free trial. Cancel anytime.
Evidence
Records-basedModerate confidence
Based on species-occurrence records, not local invertebrate surveys.
Through the year
0–3 scale · September highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.
Ranked for today
Fly box · Brown Trout
Top
6-10 · Pattern
High-confidence seasonal pick
Permits & access
Permit required — see local rules.
- RD Tolmin
- Fly-only, barbless
- Upper 1km closed (breeding water).
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 3
Water here around 19°C — probably warm enough to stress Brown Trout . These are likely cooler.
Gallery · 2
Hudourniška pregrada na Beli Terrain map
The full read · show the working · for Brown Trout · confidence 80%
How the 31 is built — score × weight = contribution
Temperature19 × 28%5.3
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity64 × 12%7.7
Limiting factor: Water temperature (19.4°C) is outside Brown Trout's preferred range (10–16°C)= 62
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Nadižaproxy
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.
Directions
Seasons & zones
- Trout 1 March → 30 September
- Marble trout 1 April → 31 October
Related guides
Booking & contacts