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