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
Mon · Today Clear
+23°+8°3%
Tue · Tomorrow Clear
+24°+12°5%
Wednesday 22/7 Clear
+21°+11°0,2 mm
Thursday 23/7 Clear
+22°+8°5%
Friday 24/7 Clear
+26°+10°8%
Saturday 25/7 Partly cloudy
+22°+9°7%
Sunday 26/7 Showers
+19°+11°6,5 mm
Monday 27/7 Partly cloudy
+25°+10°2,8 mm
Tuesday 28/7 Partly cloudy
+25°+13°0,9 mm
Wednesday 29/7 Clear
+24°+12°1,8 mm
Thursday 30/7 Clear
+21°+8°2%
Friday 31/7 Partly cloudy
+19°+10°0,6 mm
Saturday 1/8 Partly cloudy
+19°+8°17%
Sunday 2/8 Showers
+15°+11°11,1 mm
Tuesday 4/8 Rain (climate normal)
+22°+13°8,0 mm
Wednesday 5/8 Partly cloudy (climate normal)
+23°+13°20%
Thursday 6/8 Partly cloudy (climate normal)
+22°+13°20%
Friday 7/8 Rain (climate normal)
+23°+13°11,3 mm
Saturday 8/8 Partly cloudy (climate normal)
+21°+12°20%
Sunday 9/8 Partly cloudy (climate normal)
+17°+10°20%
Monday 10/8 Rain (climate normal)
+20°+11°6,5 mm
Tuesday 11/8 Partly cloudy (climate normal)
+20°+11°20%
Wednesday 12/8 Partly cloudy (climate normal)
+22°+12°20%
Thursday 13/8 Rain (climate normal)
+24°+14°4,7 mm
Friday 14/8 Partly cloudy (climate normal)
+23°+13°20%
Saturday 15/8 Partly cloudy (climate normal)
+21°+12°20%
Sunday 16/8 Rain (climate normal)
+18°+10°8,9 mm
Monday 17/8 Partly cloudy (climate normal)
+17°+10°20%
Tuesday 18/8 Partly cloudy (climate normal)
+21°+12°20%
Wednesday 19/8 Rain (climate normal)
+22°+13°11,3 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.