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