Freestone · Mixed · Castilla y León

Río Riaza

Río Riaza terrain map
Terrain map

The Riaza rises in the Sierra de Ayllón and runs through the Segovian highlands.

Poor · Brown Trout
Klinkhammer · 14-18
Poorlive now
Not the day for it
River temperature is the limiting factor today, not the flow. This is not the day to push it. Check the thermal advice above before you head out.
90% confidence
What moved it
  • Level0.01 mLast reading 12h ago
  • Water temp22.9°C
  • ClarityClear
Today’s fly
Klinkhammer
Klinkhammer14-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.01 m
Last reading 12h ago
Water temp22.9°C
ClarityClear
Weather30°C
WindSW 21 km/h
Pressure1014 hPa
Rain · recent0.0 mm
Rain · ahead0.0 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for brown trout
Warm — slow
23°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 22.9°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Hatch timeline · todayQuiet day

Hatch predictions

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 with Pro.

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Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
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
Permits & access
Permit required — see local rules.
  • Se requiere licencia de Castilla y León
  • Los tramos, incluido Rioseco, necesitan permisos separados
  • Confírmalo en el visor de pesca de la JCyL.
What's coming
Plan ahead
5-day outlook
Cooler water nearby · 1
Probably above the brown trout safety line — these are likely cooler, but carry a thermometer.
Río Duratón
21 km
~17°C
Brown trout
About this water

The Riaza rises in the Sierra de Ayllón and runs through the Segovian highlands. JCyL lists active tramos including Rioseco. The Riaza has real trout water in its upper reaches but is more conditional than the Cega or Eresma, so fishing quality varies noticeably by stretch — check current conditions and permits for the specific tramo before travelling. Best suited to anglers already in Segovia or northern Madrid rather than a dedicated long trip.

  • Mixed
The full read · show the working · for brown trout · confidence 90%
How the 4 is built — score × weight = contribution
Temperature2 × 28%0.6
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 (22.9°C) is outside Brown Trout's preferred range (10–16°C)= 58
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.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • TroutLast Sunday of March → 31 July
Related guides
Pyrenees PlaybookSpanish riversEuro Nymphingsubsurface methods
Booking & contacts