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