Where to fish

  • Forecast
  • Catches

Mine

  • Favorites

Where to fish

  • Forecast
  • Catches

Mine

  • Favorites
ForecastCatchesFavorites
AboutHow the forecast worksWhere fish livePrivacyTerms[email protected]
© 2026·AI-powered bite forecast
0.1.0+2166 · bee8965a

We use cookies for analytics and advertising. Cookies necessary for the site to function are always kept. Learn more

United Kingdom / Ceredigion / Lake Llyn Du

Bite forecast: Lake Llyn Du

  • 2 ha
Loading map…

Best fishing days for the next week

  1. MondaySeptember 7weather-based forecast
    63/100high activity

    Cloudy: 14–16 °C

Lake Llyn Du (Ceredigion) — a popular fishing spot. About 2 ha in area. See when the bite is best: hourly fish activity for the days ahead, computed from the weather, pressure, and season.

Loading map…
SundaySeptember 6weather-based forecast
62/100high activity

Clear: 14–23 °C

  • TuesdaySeptember 8weather-based forecast
    62/100high activity

    Partly cloudy: 12–15 °C

  • Bite calendar

    Friday, September 4

    Aug 31 – Sep 6
    Mon
    Tue
    Wed
    Thu
    Fri
    Sat
    Sun
    Bite activity:highmediumlowslow
    Based on:weatherseasonal
    What is a bite calendar?
    DacePikeEuropean eelRuffeWhitefishZanderBreamCarpPerchRainbow troutBrown troutWels catfishIdeRoachBleakChubCrucian carpRuddTenchWhite bream

    Bleak

    3/10 · Weak

    Hourly activity

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

    The bite is weak — fish are sluggish. 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

    A slow day — go only if you really feel like it.

    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 rising 9 hPa over the day — the bite usually settles down after a rise.

    Pressure through the day, 9 hPa change
    00:00 · 101123:00 · 1020 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

    4 SepFriday, September 4
    +16°

    Cloudy · feels like +12°

    Low / high
    +14°…+18°
    Precipitation
    0.0 mm
    Wind
    16 mph W
    Cloud cover
    100%
    Humidity
    70%
    Pressure
    1015 hPa
    00:00+18°—16 mphsouthwest wind, 16 mph88%100%
    01:00+18°0.1 mm17 mphsouthwest wind, 17 mph91%100%
    02:00+18°0.4 mm17 mphsouthwest wind, 17 mph95%100%
    03:00+18°0.8 mm15 mphsouthwest wind, 15 mph96%100%
    04:00+15°2.1 mm10 mphnorthwest wind, 10 mph99%100%
    05:00+15°5.2 mm11 mphwest wind, 11 mph99%100%
    06:00+15°5.1 mm13 mphwest wind, 13 mph99%100%
    07:00+14°2.1 mm10 mphwest wind, 10 mph95%100%
    08:00+15°—11 mphwest wind, 11 mph92%100%
    09:00+15°—13 mphwest wind, 13 mph86%100%
    10:00+15°—15 mphwest wind, 15 mph71%100%
    11:00+16°—16 mphwest wind, 16 mph69%100%
    12:00+16°—16 mphwest wind, 16 mph70%100%
    13:00+16°—15 mphwest wind, 15 mph68%100%
    14:00+16°—14 mphwest wind, 14 mph67%100%
    15:00+16°—15 mphwest wind, 15 mph68%100%
    16:00+17°—15 mphwest wind, 15 mph67%100%
    17:00+17°—15 mphwest wind, 15 mph69%27%
    18:00+16°—16 mphwest wind, 16 mph66%2%
    19:00+16°—13 mphwest wind, 13 mph70%59%
    20:00+15°—12 mphwest wind, 12 mph72%0%
    21:00+15°—12 mphwest wind, 12 mph71%0%
    22:00+15°—12 mphwest wind, 12 mph73%0%
    23:00+15°—13 mphwest wind, 13 mph70%60%
    +18°+16°+14°
    Weather throughout the day
    0:006:0012:0018:0023:00

    Sun and moon

    Friday, September 4
    The day: daylight and the hours the moon is above the horizon. Local time0:0012:0024:00
    DaylightMoon above the horizon
    Sunrise
    06:32
    Sunset
    19:57
    Day length
    13 h 25 min
    Sunshine hours
    7 h 17 min
    UV index
    3
    moderate
    Moon
    Last quarter
    Moonrise
    22:44
    Moonset
    16:05

    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

    +14% in the windowFriday, September 4
    Feeding windows on the day scale, local time0:0012:0024:00
    Major periodsMinor periods
    • Major05:55–07:55Moon overhead
    • Minor15:35–16:35Moonset
    • Major18:26–20:26Moon underfoot
    • Minor22:14–23:14Moonrise

    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 Claerddu0.9 mi
    • Afon Claerwen1 mi
    • River Ystwyth3 mi

    Nearby water bodies

    • LakeLlyn Fyrddon fach0.3 mi
    • LakeLlyn Fryddon fawr0.5 mi
    • LakeLlyn Hir2 mi
    • LakeLlyn Egnant2 mi
    • LakeLlyn Teifi2 mi
    • ReservoirLlyn Pond Gwaith2 mi
    • LakeLlyn y Gorlan2 mi
    • LakeLlyn Bach2 mi
    • LakeLlyn Cerig Uwydion uchaf3 mi
    • LakeLlyn Cerif Uwydion isaf3 mi