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 — Skien
14 real + 16 synthesised
Sat · Today Showers
+16°+9°10,6 mm
Sun · Tomorrow Cloudy
+19°+9°9%
Monday 7/9 Showers
+19°+10°7,4 mm
Tuesday 8/9 Clear
+18°+10°0,2 mm
Wednesday 9/9 Fog
+14°+7°0,8 mm
Thursday 10/9 Showers
+14°+9°13,6 mm
Friday 11/9 Cloudy
+15°+7°15%
Saturday 12/9 Cloudy
+16°+9°11%
Sunday 13/9 Clear
+18°+9°7%
Monday 14/9 Showers
+12°+8°0,8 mm
Tuesday 15/9 Cloudy
+14°+9°0,2 mm
Wednesday 16/9 Showers
+13°+10°2,0 mm
Thursday 17/9 Showers
+10°+6°9,9 mm
Friday 18/9 Clear
+14°+5°5%
Saturday 19/9 Rain (climate normal)
+17°+9°8,1 mm
Sunday 20/9 Partly cloudy (climate normal)
+18°+9°20%
Monday 21/9 Partly cloudy (climate normal)
+17°+9°20%
Tuesday 22/9 Rain (climate normal)
+18°+9°11,4 mm
Wednesday 23/9 Partly cloudy (climate normal)
+16°+8°20%
Thursday 24/9 Partly cloudy (climate normal)
+12°+6°20%
Friday 25/9 Rain (climate normal)
+15°+7°6,6 mm
Saturday 26/9 Partly cloudy (climate normal)
+15°+7°20%
Sunday 27/9 Partly cloudy (climate normal)
+17°+8°20%
Monday 28/9 Rain (climate normal)
+19°+10°4,8 mm
Tuesday 29/9 Partly cloudy (climate normal)
+18°+9°20%
Wednesday 30/9 Partly cloudy (climate normal)
+16°+8°20%
Thursday 1/10 Rain (climate normal)
+7°+2°8,4 mm
Friday 2/10 Partly cloudy (climate normal)
+6°+2°20%
Saturday 3/10 Partly cloudy (climate normal)
+10°+4°20%
Sunday 4/10 Rain (climate normal)
+11°+5°10,6 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.