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© 2026·AI-powered bite forecast
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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

  2. MondaySeptember 7weather-based forecast
    62/100high activity

    Cloudy: 12–15 °C

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

    Cloudy: 14–18 °C

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.

Loading map…

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

Bite calendar

Aug 31 – Sep 6
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Bite activity:highmediumlowslow
Based on:weatherseasonal
What is a bite calendar?
European eelPikeBarbelDaceGraylingRuffeWhitefishZanderWels catfishPerchAtlantic salmonBreamBrown troutCarpRainbow troutIdeChubCrucian 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. A thunderstorm is possible: activity rises before the front and drops after.

Peak bite hours

Best time — 06:00–08:00 (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. A thunderstorm is possible — bring a rain jacket, and pack up at the first rumble of thunder.

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 6 hPa over the day — fish are usually more active ahead of a weather change.

Pressure through the day, 6 hPa change
00:00 · 101523:00 · 1010 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

2 SepWednesday, September 2
+16°

Drizzle · feels like +17°

Low / high
+14°…+20°
Precipitation
0.4 mm
Wind
8 mph SE
Cloud cover
100%
Humidity
95%
Pressure
1011 hPa
00:00+14°—2 mphsouth wind, 2 mph96%98%
01:00+14°—3 mphsouth wind, 3 mph96%100%
02:00+14°—4 mphsouth wind, 4 mph95%100%
03:00+14°—4 mphsoutheast wind, 4 mph96%100%
04:00+15°—4 mphsoutheast wind, 4 mph96%100%
05:00+15°—5 mphsoutheast wind, 5 mph95%100%
06:00+15°—5 mphsoutheast wind, 5 mph95%100%
07:00+14°—5 mpheast wind, 5 mph97%100%
08:00+15°0.1 mm6 mpheast wind, 6 mph96%100%
09:00+15°0.2 mm6 mpheast wind, 6 mph96%100%
10:00+15°0.1 mm7 mpheast wind, 7 mph96%100%
11:00+16°—8 mphsoutheast wind, 8 mph92%100%
12:00+16°0.4 mm8 mphsoutheast wind, 8 mph95%100%
13:00+17°2.0 mm6 mphsoutheast wind, 6 mph96%100%
14:00+17°2.5 mm4 mphsoutheast wind, 4 mph95%100%
15:00+18°—2 mphsouth wind, 2 mph92%96%
16:00+20°—5 mphsouthwest wind, 5 mph90%81%
17:00+19°0.6 mm10 mphwest wind, 10 mph88%81%
18:00+19°—10 mphsouthwest wind, 10 mph86%88%
19:00+19°—7 mphsouthwest wind, 7 mph84%98%
20:00+18°—10 mphsouthwest wind, 10 mph85%64%
21:00+17°—8 mphsouthwest wind, 8 mph89%100%
22:00+17°—9 mphsouthwest wind, 9 mph94%100%
23:00+17°—9 mphsouthwest wind, 9 mph93%100%
+20°+17°+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
06:37
Sunset
20:18
Day length
13 h 41 min
Sunshine hours
2 h
UV index
1
low
Moon
Waning gibbous
Moonrise
21:24
Moonset
13:52

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 windowWednesday, September 2
Feeding windows on the day scale, local time0:0012:0024:00
Major periodsMinor periods
  • Major04:16–06:16Moon overhead
  • Minor13:22–14:22Moonset
  • Major16:44–18:44Moon underfoot
  • Minor20:54–21:54Moonrise

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?