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