Freestone · Mixed · Castilla y León, ES

Río Riaza

DSC 0262 Hoces del río Riaza

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

Poor · Brown Trout
Pheasant Tail Nymph · 14–18
Closed season
Out of season. Try elsewhere.
Closed — confidence not applicable today.
What moved it
  • Level0.02 mLast reading 7h ago
  • Water temp3.8°C
  • ClarityClear
Today's fly
Pheasant Tail Nymph
Pheasant Tail Nymph14–18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
0.02 m
Last reading 7h ago
Water temp3.8°C
ClarityClear
Weather7°C
WindSW 12 km/h
Pressure1013 hPa
Rain · recent22.2 mm
Rain · ahead8.4 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Brown Trout
Cool — slow
4°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.
Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 2 guilds as a supporter.

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Evidence
Survey-backed · regionalHigh confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

Through the year
0–3 scale · November highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Trout seasonSeason
1
2
2
2
1
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1
Blue Winged OliveHatch
1
2
2
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.
  • Castilla y León licence required
  • Tramos including Rioseco need separate permits
  • Confirm on the JCyL pesca visor.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Río Duratón
21 km
0
Brown trout
Río Madarquillos (TPE II)
28 km
0
Brown trout
Río Cega
36 km
0
Brown trout
Embalses de Riosequillo & Puentes Viejas
36 km
Brown trout
Embalse de El Atazar
41 km
Black bass · Pike · Carp
Gallery · 2
  1. DSC 0262 Hoces del río Riaza
  2. Terrain map of the venue
    Terrain map
About this water

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 50%
How the 0 is built — score × weight = contribution
Temperature11 × 28%3.1
Flow15 × 22%3.3
Clarity95 × 18%17.1
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity50 × 12%6.0
Limiting factor: Water temperature (3.8°C) is outside Brown Trout's preferred range (10–16°C)= 44
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
Warmer water — toward the 10–16 °C ideal band — would lift the temperature score.
A drop and clear would lift the flow and clarity scores.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout Last Sunday of March → 31 July
Related guides
Pyrenees PlaybookSpanish riversEuro Nymphingsubsurface methods
Booking & contacts
At a glance

Río Riaza is a freestone river in Castilla y León, Spain. It sits at about 1,192 m above sea level. The river is described as roughly 113 km long. The species listed for this water is brown trout. The trout season is recorded as running from Last Sunday of March to 31 July. Best window recorded for anglers: May–June for the upper / Rioseco reach. Core methods listed: short-line nymph; dry fly. Level and flow data for this water is linked from the gauge “EA009 Riaza en Riaza (upper)”. Nearby waters in our listings include Río Duratón at 21 km, Río Madarquillos (TPE II) at 28 km and Río Cega at 36 km.