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