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