Days 1-14 are a real forecast from global weather models. Days 15-30 are season-typical values based on climate normals 1991-2020 (MET) — good for planning, NOT an exact forecast that far ahead.
30 days — Arendal
14 real + 16 synthesised
Tue · Today Clear
+23°+12°3%
Wed · Tomorrow Partly cloudy
+21°+13°0,5 mm
Thursday 23/7 Partly cloudy
+20°+12°6%
Friday 24/7 Clear
+22°+11°6%
Saturday 25/7 Showers
+15°+13°3,7 mm
Sunday 26/7 Clear
+21°+13°11%
Monday 27/7 Clear
+19°+9°5%
Tuesday 28/7 Clear
+20°+11°5%
Wednesday 29/7 Clear
+25°+12°3%
Thursday 30/7 Clear
+23°+14°2%
Friday 31/7 Clear
+26°+11°3%
Saturday 1/8 Clear
+23°+15°6%
Sunday 2/8 Thunderstorm
+22°+15°0,6 mm
Monday 3/8 Partly cloudy
+19°+13°17%
Tuesday 4/8 Rain (climate normal)
+20°+12°9,8 mm
Wednesday 5/8 Partly cloudy (climate normal)
+25°+14°20%
Thursday 6/8 Partly cloudy (climate normal)
+25°+15°20%
Friday 7/8 Rain (climate normal)
+21°+12°5,9 mm
Saturday 8/8 Partly cloudy (climate normal)
+20°+12°20%
Sunday 9/8 Partly cloudy (climate normal)
+19°+11°20%
Monday 10/8 Rain (climate normal)
+20°+11°8,3 mm
Tuesday 11/8 Partly cloudy (climate normal)
+20°+12°20%
Wednesday 12/8 Partly cloudy (climate normal)
+24°+14°20%
Thursday 13/8 Rain (climate normal)
+23°+13°5,3 mm
Friday 14/8 Partly cloudy (climate normal)
+22°+13°20%
Saturday 15/8 Partly cloudy (climate normal)
+20°+12°20%
Sunday 16/8 Rain (climate normal)
+20°+12°9,2 mm
Monday 17/8 Partly cloudy (climate normal)
+18°+10°20%
Tuesday 18/8 Partly cloudy (climate normal)
+23°+13°20%
Wednesday 19/8 Rain (climate normal)
+23°+14°5,9 mm
How does the long-range forecast work?
Days 1-14: Fetched live from global weather models (ECMWF, GFS) with statistical correction. Reliability about 85 % for days 1-3, about 60 % for days 7-10, about 45 % for days 11-14.
Days 15-30: A real forecast does not exist that far ahead (chaotic system). Instead we show season-typical values: the monthly average Tmax/Tmin from climate normals 1991-2020, with mild weekly variation.
Use: «About how warm is it usually in Oslo the last week of July?» — a good question for days 15-30. «Will it rain on 27 May?» — no serious forecast can answer that.