Days 1-14 are a real forecast from global weather models. Days 15-30 are season-typical values based on SMHI climate normals 1991-2020 — good for planning, NOT an exact forecast that far ahead.
30 days — Västerås
14 real + 16 synthesised
Wed · Today Showers
+20°+15°9,0 mm
Thu · Tomorrow Partly cloudy
+22°+15°0,5 mm
Friday 7/8 Clear
+22°+13°0,4 mm
Saturday 8/8 Partly cloudy
+21°+12°9%
Sunday 9/8 Partly cloudy
+24°+11°0,4 mm
Monday 10/8 Showers
+21°+12°0,4 mm
Tuesday 11/8 Clear
+20°+10°0,2 mm
Wednesday 12/8 Clear
+21°+9°2%
Thursday 13/8 Clear
+21°+9°0,4 mm
Friday 14/8 Drizzle
+14°+12°2,2 mm
Saturday 15/8 Showers
+15°+12°2,7 mm
Sunday 16/8 Partly cloudy
+20°+13°18,0 mm
Monday 17/8 Partly cloudy
+18°+14°3,8 mm
Tuesday 18/8 Partly cloudy
+21°+14°0,1 mm
Wednesday 19/8 Rain (climate normal)
+20°+11°4,4 mm
Thursday 20/8 Partly cloudy (climate normal)
+24°+13°20%
Friday 21/8 Partly cloudy (climate normal)
+25°+14°20%
Saturday 22/8 Rain (climate normal)
+22°+12°7,9 mm
Sunday 23/8 Partly cloudy (climate normal)
+21°+11°20%
Monday 24/8 Partly cloudy (climate normal)
+20°+10°20%
Tuesday 25/8 Rain (climate normal)
+19°+10°6,4 mm
Wednesday 26/8 Partly cloudy (climate normal)
+22°+12°20%
Thursday 27/8 Partly cloudy (climate normal)
+23°+12°20%
Friday 28/8 Rain (climate normal)
+25°+13°6,2 mm
Saturday 29/8 Partly cloudy (climate normal)
+22°+12°20%
Sunday 30/8 Partly cloudy (climate normal)
+20°+11°20%
Monday 31/8 Rain (climate normal)
+18°+9°7,9 mm
Tuesday 1/9 Partly cloudy (climate normal)
+16°+7°20%
Wednesday 2/9 Partly cloudy (climate normal)
+18°+8°20%
Thursday 3/9 Rain (climate normal)
+18°+8°5,0 mm
How does the long-range forecast work?
Days 1-14: Fetched live from global weather models (ECMWF, GFS) with statistical correction. Reliability ~85% for days 1-3, ~60% for days 7-10, ~45% for days 11-14.
Days 15-30: A real forecast does not exist that far ahead (a chaotic system). Instead we show season-typical values: the month’s average Tmax/Tmin from SMHI climate normals 1991-2020 (Stockholm baseline with latitude correction for Västerås), with mild weekly variation.
Use: "Roughly how warm is it usually in Stockholm in the last week of July?" — a good question for days 15-30. "Will it rain on 27 May?" — no serious forecast can say.