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© 2026·AI-powered bite forecast
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United Kingdom / Carmarthenshire / Reservoir Llyn y Fan Fach

Bite forecast: Reservoir Llyn y Fan Fach

  • 11 ha
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Best fishing days for the next week

  1. ThursdaySeptember 3weather-based forecast
    59/100medium activity

    Cloudy: 16–19 °C

  2. WednesdaySeptember 2weather-based forecast
    58/100medium activity

    Drizzle: 15–19 °C

  3. TuesdaySeptember 8weather-based forecast
    58/100medium activity

    Drizzle: 12–18 °C

Reservoir Llyn y Fan Fach (Carmarthenshire) — a popular fishing spot. About 11 ha in area. Nearby towns: Brynamman and Ammanford. See when the bite is best: hourly fish activity for the days ahead, computed from the weather, pressure, and season.

Nearby towns

  • Brynamman7 mi
  • Ammanford12 mi
Loading map…

Bite calendar

Wednesday, September 2

Aug 31 – Sep 6
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Bite activity:highmediumlowslow
Based on:weatherseasonal
What is a bite calendar?
DaceEuropean eelPikeRuffeZanderPerchWhitefishBreamBrown troutCarpWels catfishRainbow troutChubIdeRoachBleakCrucian carpWhite breamRuddTench

Bleak

4/10 · Weak

Hourly activity

0:006:0012:0018:0023:00
Bite activity:highmediumlow

The bite is moderate — fish feed in short bursts. A thunderstorm is possible: activity rises before the front and drops after.

Peak bite hours

Best time — 11:00–17:00 (daytime activity).

Tactics

Chum one spot near a drop-off and wait for fish to arrive — don't chase them.

Lures

Today's bait — maggot or small hook with dough bait. In cold or murky water, add scent to your chum.

Gear

No special gear needed — seasonal clothing will do. A thunderstorm is possible — bring a rain jacket, and pack up at the first rumble of thunder.

Summary

An average day — best chances during peak windows.

How this forecast is calculated

Why this forecast

The computed water temperature is around 16 °C — inside the 14–26 °C comfort range for Bleak, so baseline activity is high.

Computed water temperature by month; the green band is the 14–26 °C comfort rangecomfort 14–26 °C16 °C
JFMAMJJASOND

Bleak feeds by day — between sunrise and sunset; their times are in the sun-and-moon card above.

The day: daylight hours and when Bleak feeds0:0012:0024:00

Pressure is dropping 3 hPa over the day — fish are usually more active ahead of a weather change.

Pressure through the day, 3 hPa change
00:00 · 102023:00 · 1017 hPa

One more input — the moon's feeding windows: within their hours the score sits higher than across the rest of the day. The window times are in the “Solunar feeding periods” card below.

Feeding windows on the day scale0:0012:0024:00

September is a slow season for Bleak: the best months fall at another time of year.

JFMAMJJASOND

These are the same values the bite curve above was computed from. How the forecast works

2 SepWednesday, September 2
+18°

Drizzle · feels like +16°

Low / high
+14°…+19°
Precipitation
0.1 mm
Wind
16 mph SW
Cloud cover
100%
Humidity
97%
Pressure
1016 hPa
00:00+14°0.1 mm3 mphwest wind, 3 mph98%100%
01:00+14°—4 mphsouthwest wind, 4 mph97%100%
02:00+14°0.1 mm2 mphsouth wind, 2 mph98%100%
03:00+15°4.5 mm5 mphsouthwest wind, 5 mph97%100%
04:00+15°0.1 mm6 mphsouth wind, 6 mph97%100%
05:00+15°—8 mphsouth wind, 8 mph96%100%
06:00+16°—11 mphsouth wind, 11 mph96%100%
07:00+15°1.0 mm12 mphsouth wind, 12 mph99%100%
08:00+16°0.6 mm14 mphsouth wind, 14 mph98%100%
09:00+16°1.9 mm14 mphsouthwest wind, 14 mph98%100%
10:00+17°2.0 mm17 mphsouthwest wind, 17 mph99%100%
11:00+17°0.1 mm17 mphsouthwest wind, 17 mph97%100%
12:00+18°0.1 mm16 mphsouthwest wind, 16 mph97%100%
13:00+18°0.2 mm15 mphsouthwest wind, 15 mph96%100%
14:00+18°0.3 mm15 mphsouthwest wind, 15 mph95%100%
15:00+19°1.3 mm13 mphsouthwest wind, 13 mph96%100%
16:00+19°—12 mphsouthwest wind, 12 mph91%93%
17:00+18°—11 mphsouthwest wind, 11 mph92%100%
18:00+18°—11 mphsouthwest wind, 11 mph90%95%
19:00+18°—11 mphsouthwest wind, 11 mph90%89%
20:00+17°—11 mphsouthwest wind, 11 mph91%99%
21:00+17°—9 mphsouthwest wind, 9 mph92%100%
22:00+17°—9 mphsouthwest wind, 9 mph96%100%
23:00+17°0.2 mm12 mphsouthwest wind, 12 mph99%100%
+19°+16°+14°
Weather throughout the day
0:006:0012:0018:0023:00

Sun and moon

Wednesday, September 2
The day: daylight and the hours the moon is above the horizon. Local time0:0012:0024:00
DaylightMoon above the horizon
Sunrise
06:30
Sunset
20:01
Day length
13 h 31 min
Sunshine hours
0 min
UV index
1
low
Moon
Waning gibbous
Moonrise
21:25
Moonset
13:18

The day is 4 min shorter than yesterday.

Sunshine hours count direct sun only — cloud cover cuts it, so it is shorter than daylight.

Solunar feeding periods

+13% in the windowWednesday, September 2
Feeding windows on the day scale, local time0:0012:0024:00
Major periodsMinor periods
  • Major04:00–06:00Moon overhead
  • Minor12:48–13:48Moonset
  • Major16:27–18:27Moon underfoot
  • Minor20:55–21:55Moonrise

The windows are set by the moon's transit and rise, and the forecast above already accounts for them: within these hours the bite score sits higher than across the rest of the day, while the day's overall level still comes from the catch-calibrated model.

What are solunar periods?

Nearby rivers

  • Afon Twrch1 mi
  • River Usk2 mi
  • Afon Hydfer3 mi
  • Sawdde Fechan4 mi
  • Afon Sawdde5 mi
  • Afon Tawe6 mi
  • Nant Garw6 mi
  • River Giedd6 mi
  • Nant Llech7 mi
  • River Amman7 mi

Nearby water bodies

  • LakeLlyn y Fan Fawr2 mi
  • ReservoirUsk Reservoir4 mi
  • ReservoirCrai Reservoir5 mi