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 — Trondheim
14 real + 16 synthesised
Mon · Today Clear
+16°+7°8%
Tue · Tomorrow Drizzle
+13°+11°10,5 mm
Wednesday 22/7 Showers
+13°+10°2,2 mm
Thursday 23/7 Partly cloudy
+14°+9°0,2 mm
Friday 24/7 Partly cloudy
+14°+9°1,0 mm
Saturday 25/7 Showers
+15°+11°2,8 mm
Sunday 26/7 Showers
+15°+10°2,8 mm
Monday 27/7 Partly cloudy
+16°+11°18%
Tuesday 28/7 Showers
+15°+10°3,0 mm
Wednesday 29/7 Drizzle
+12°+10°37,2 mm
Thursday 30/7 Showers
+13°+9°8,6 mm
Friday 31/7 Showers
+14°+9°0,6 mm
Saturday 1/8 Partly cloudy
+14°+8°16%
Sunday 2/8 Clear
+17°+8°0,5 mm
Monday 3/8 Rain (climate normal)
+17°+10°9,9 mm
Tuesday 4/8 Partly cloudy (climate normal)
+19°+12°20%
Wednesday 5/8 Partly cloudy (climate normal)
+20°+12°20%
Thursday 6/8 Rain (climate normal)
+18°+11°6,7 mm
Friday 7/8 Partly cloudy (climate normal)
+18°+11°20%
Saturday 8/8 Partly cloudy (climate normal)
+16°+10°20%
Sunday 9/8 Rain (climate normal)
+17°+10°5,2 mm
Monday 10/8 Partly cloudy (climate normal)
+20°+12°20%
Tuesday 11/8 Partly cloudy (climate normal)
+22°+13°20%
Wednesday 12/8 Rain (climate normal)
+21°+13°9,9 mm
Thursday 13/8 Partly cloudy (climate normal)
+21°+13°20%
Friday 14/8 Partly cloudy (climate normal)
+17°+10°20%
Saturday 15/8 Rain (climate normal)
+16°+10°10,4 mm
Sunday 16/8 Partly cloudy (climate normal)
+17°+10°20%
Monday 17/8 Partly cloudy (climate normal)
+18°+11°20%
Tuesday 18/8 Rain (climate normal)
+19°+12°7,5 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.