Days 1-14 are a real forecast from weather models. Days 15-30 are season-typical values based on 1991-2020 climate averages — good for planning, NOT an exact forecast that far ahead.
30 days — Letterkenny
14 real + 16 synthesised
Thu · Today Showers
17°8°0.8 mm
Fri · Tomorrow Fog
18°7°1.9 mm
Saturday 1/8 Sunny
19°7°0.1 mm
Sunday 2/8 Sunny intervals
20°7°11%
Monday 3/8 Sunny intervals
17°8°0.6 mm
Tuesday 4/8 Cloudy
14°12°36%
Wednesday 5/8 Fog
17°9°3.8 mm
Thursday 6/8 Sunny intervals
17°6°14%
Friday 7/8 Sunny
19°6°11%
Saturday 8/8 Sunny
21°7°6%
Sunday 9/8 Sunny
21°7°5%
Monday 10/8 Sunny intervals
18°7°28%
Tuesday 11/8 Sunny
23°10°14%
Wednesday 12/8 Sunny
25°11°9%
Thursday 13/8 Rain (climate average)
27°17°5.5 mm
Friday 14/8 Sunny intervals (climate average)
29°18°20%
Saturday 15/8 Sunny intervals (climate average)
30°18°20%
Sunday 16/8 Rain (climate average)
28°17°4.2 mm
Monday 17/8 Sunny intervals (climate average)
24°15°20%
Tuesday 18/8 Sunny intervals (climate average)
24°15°20%
Wednesday 19/8 Rain (climate average)
25°16°5.7 mm
Thursday 20/8 Sunny intervals (climate average)
27°17°20%
Friday 21/8 Sunny intervals (climate average)
30°18°20%
Saturday 22/8 Rain (climate average)
30°18°5.1 mm
Sunday 23/8 Sunny intervals (climate average)
26°16°20%
Monday 24/8 Sunny intervals (climate average)
25°15°20%
Tuesday 25/8 Rain (climate average)
25°15°4.6 mm
Wednesday 26/8 Sunny intervals (climate average)
24°15°20%
Thursday 27/8 Sunny intervals (climate average)
28°17°20%
Friday 28/8 Rain (climate average)
29°18°7.5 mm
How does the long-range forecast work?
Days 1-14: Fetched live from weather models (UKV, ECMWF, GFS) with statistical correction. Reliability ~85% for days 1-3, ~60% for days 7-10, ~45% for days 11-14.
Days 15-30: A real forecast does not exist that far ahead (a chaotic system). Instead we show season-typical values: the month’s average max/min from 1991-2020 climate data (London baseline with latitude correction for Letterkenny), with mild weekly variation.
Use: "Roughly how warm is it usually in London in the last week of July?" — a good question for days 15-30. "Will it rain on 27 May?" — no serious forecast can say.
Forecasts from the UK Met Office UKV model, global weather models and official UK environmental data · Met Office UKV model · Environment Agency · Copernicus CAMS · NOAA