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+2163 · 92c14a40

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

United Kingdom / County Tyrone / River Derg

Bite forecast: River Derg

  • length 71 km
Loading map…

Best fishing days for the next week

  1. WednesdaySeptember 9weather-based forecast
    64/100high activity

    Partly cloudy: 8–13 °C

Loading map…

River Derg (County Tyrone) — a spot well known among anglers. About 71 km long. See when the bite is best: hourly fish activity for the days ahead, computed from the weather, pressure, and season.

Nearby rivers

  • Mourne Beg2 mi
  • Glendergan River6 mi
  • Mourne Beg River7 mi
  • Leaghanu River7 mi
  • Fairy Water7 mi
  • Glendargan River8 mi
  • The Black Water9 mi

Nearby water bodies

  • LakeLough a Yelvin4 mi
  • LakeLoughnaboy4 mi
  • LakeLough Any4 mi
  • LakeLough Lee5 mi
  • LakeLough Lack5 mi
  • LakeLough Corr6 mi
  • LakeLough Doo6 mi
  • LakeMagheralough7 mi
  • LakeLough Bradan7 mi
  • LakeLough Bradan7 mi
MondaySeptember 7weather-based forecast
62/100high activity

Cloudy: 12–15 °C

  • ThursdaySeptember 3weather-based forecast
    58/100medium activity

    Cloudy: 14–18 °C

  • Bite calendar

    Aug 31 – Sep 6
    Mon
    Tue
    Wed
    Thu
    Fri
    Sat
    Sun
    Bite activity:highmediumlowslow
    Based on:weatherseasonal
    What is a bite calendar?
    WhitefishBarbelDaceEuropean eelGraylingPikeRuffeZanderBreamWels catfishPerchAtlantic salmonBrown troutCarpIdeRainbow troutChubCrucian carpRoachBleakRuddTenchWhite bream

    Atlantic salmon

    6/10 · Fair

    Hourly activity

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

    The bite is strong — fish are active. Pressure is dropping — this usually boosts the bite.

    Peak bite hours

    Best time — 07:00–08:00 (dawn bite) and 20:00–22:00 (dusk bite).

    Tactics

    Work the cover — snags, weed edges, hole entrances; retrieve the lure with pauses.

    Lures

    The water's turning murky — go with bright, noisy lures: salmon spoon or salmon fly.

    Gear

    No special gear needed — seasonal clothing will do. Rain is expected — don't forget a rain jacket or a waterproof shell.

    Summary

    Worth going — it's a productive day.

    How this forecast is calculated

    Why this forecast

    The computed water temperature is around 15 °C — warmer than the 4–14 °C comfort range for Atlantic salmon: in the heat it drops deeper and feeds less often.

    Computed water temperature by month; the green band is the 4–14 °C comfort rangecomfort 4–14 °C15 °C
    JFMAMJJASOND

    Atlantic salmon works the twilight: the peaks are pinned to sunrise and sunset — their times are in the sun-and-moon card above.

    The day: daylight hours and when Atlantic salmon feeds0:0012:0024:00

    Pressure is dropping 1 hPa over the day — fish are usually more active ahead of a weather change.

    Pressure through the day, 1 hPa change
    00:00 · 101123:00 · 1009 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 an active season for Atlantic salmon here.

    JFMAMJJASOND

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

    6 SepSunday, September 6
    +18°

    Drizzle · feels like +17°

    Low / high
    +13°…+20°
    Precipitation
    1.1 mm
    Wind
    14 mph SSW
    Cloud cover
    74%
    Humidity
    93%
    Pressure
    1004 hPa
    00:00+17°0.3 mm15 mphsouth wind, 15 mph94%100%
    01:00+17°0.3 mm16 mphsouth wind, 16 mph94%100%
    02:00+17°0.1 mm15 mphsouth wind, 15 mph94%100%
    03:00+17°0.1 mm14 mphsouth wind, 14 mph93%100%
    04:00+17°0.1 mm13 mphsouth wind, 13 mph93%100%
    05:00+17°0.1 mm13 mphsouth wind, 13 mph93%100%
    06:00+17°0.1 mm14 mphsouth wind, 14 mph92%100%
    07:00+17°0.1 mm14 mphsouth wind, 14 mph92%100%
    08:00+17°—14 mphsouth wind, 14 mph91%100%
    09:00+18°—15 mphsouth wind, 15 mph90%100%
    10:00+18°—15 mphsouth wind, 15 mph90%100%
    11:00+18°1.1 mm15 mphsouth wind, 15 mph91%89%
    12:00+18°1.1 mm14 mphsouth wind, 14 mph93%74%
    13:00+18°1.1 mm14 mphsouth wind, 14 mph93%66%
    14:00+19°0.5 mm14 mphsouthwest wind, 14 mph91%74%
    15:00+20°0.5 mm14 mphsouthwest wind, 14 mph88%89%
    16:00+20°0.5 mm14 mphsouthwest wind, 14 mph86%100%
    17:00+19°0.2 mm13 mphwest wind, 13 mph85%100%
    18:00+17°0.2 mm13 mphwest wind, 13 mph85%100%
    19:00+15°0.2 mm12 mphwest wind, 12 mph85%100%
    20:00+14°—11 mphwest wind, 11 mph86%100%
    21:00+14°—9 mphwest wind, 9 mph88%100%
    22:00+13°—9 mphwest wind, 9 mph90%100%
    23:00+13°—8 mphwest wind, 8 mph91%100%
    +20°+17°+13°
    Weather throughout the day
    0:006:0012:0018:0023:00

    Sun and moon

    Sunday, September 6
    The day: daylight and the hours the moon is above the horizon. Local time0:0012:0024:00
    DaylightMoon above the horizon
    Sunrise
    06:45
    Sunset
    20:08
    Day length
    13 h 23 min
    Sunshine hours
    3 h 25 min
    UV index
    4
    moderate
    Moon
    Waning crescent
    Moonrise
    —
    Moonset
    18:36

    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 windowSunday, September 6
    Feeding windows on the day scale, local time0:0012:0024:00
    Major periodsMinor periods
    • Major08:17–10:17Moon overhead
    • Minor18:06–19:06Moonset
    • Major20:48–22:48Moon underfoot

    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?