Mayflies
- Ecology: Unknown
- Chemical: Unknown
Rules at a glance
- Free fishing
- Fly only
Water temperature for Brown Trout
Ideal11°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
Excellent — water temperature is right today, though insect activity could be better.
Likely species
Mayflies
- Large dark oliveMost likely#14–16 · EmergerDead-drift the emerger — it's sitting in the film.
- Green drakeAlso possibleLower confidence#8–10 · DunDuns are up — the Spent Gnat spinners fall at dusk.
Hatch timeline · todayQuiet day
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 3 guilds 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 · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
1
Grayling seasonSeason
1
2
2
1
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.
- Local fiskekort required from Inatur.no or regional river manager
- Inland trout-and-grayling rules
- No national salmon fee.
What's coming
Plan ahead
5-day outlook
Gallery · 2
Storåne (Hallingdalselva), Hovet, Norway Terrain map
Water quality (WFD)
The full read · show the working · for Brown Trout · confidence 75%
How the 83 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity45 × 12%5.4
Conditions total= 83
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
Directions
Seasons & zones
- Trout 1 June → 15 September
- Grayling 1 June → 15 September
Related guides
Booking & contacts
Hallingdalselva
Water temperature for Brown Trout
Ideal11°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
Excellent — water temperature is right today, though insect activity could be better.
Likely species
Mayflies
- Large dark oliveMost likely#14–16 · EmergerDead-drift the emerger — it's sitting in the film.
- Green drakeAlso possibleLower confidence#8–10 · DunDuns are up — the Spent Gnat spinners fall at dusk.
Hatch timeline · todayQuiet day
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 3 guilds 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 · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
1
Grayling seasonSeason
1
2
2
1
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.
- Local fiskekort required from Inatur.no or regional river manager
- Inland trout-and-grayling rules
- No national salmon fee.
What's coming
Plan ahead
5-day outlook
Gallery · 2
Storåne (Hallingdalselva), Hovet, Norway Terrain map
Water quality (WFD)
- Ecology: Unknown
- Chemical: Unknown
The full read · show the working · for Brown Trout · confidence 75%
How the 83 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity45 × 12%5.4
Conditions total= 83
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
Directions
Seasons & zones
- Trout 1 June → 15 September
- Grayling 1 June → 15 September
Related guides
Booking & contacts