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.
The forecast for Sandefjord and the places around it comes from the same weather models as the place pages. Radar: RainViewer, images from the last two hours.
30 days — Sandefjord
14 real + 16 synthesised
Fri · Today Showers
+15°+10°2,0 mm
Sat · Tomorrow Clear
+16°+10°1,4 mm
Sunday 4/10 Cloudy
+15°+8°0,1 mm
Monday 5/10 Cloudy
+18°+11°0,6 mm
Tuesday 6/10 Cloudy
+17°+7°7%
Wednesday 7/10 Clear
+14°+5°7%
Thursday 8/10 Cloudy
+11°+5°14%
Friday 9/10 Cloudy
+11°+3°2,6 mm
Saturday 10/10 Showers
+14°+9°3,1 mm
Sunday 11/10 Cloudy
+13°+6°11%
Monday 12/10 Clear
+9°+3°17%
Tuesday 13/10 Cloudy
+10°+2°13%
Wednesday 14/10 Cloudy
+14°+9°19%
Thursday 15/10 Cloudy
+12°+7°22%
Friday 16/10 Rain (climate normal)
+10°+4°8,7 mm
Saturday 17/10 Partly cloudy (climate normal)
+11°+4°20%
Sunday 18/10 Partly cloudy (climate normal)
+11°+5°20%
Monday 19/10 Rain (climate normal)
+11°+4°5,6 mm
Tuesday 20/10 Partly cloudy (climate normal)
+8°+3°20%
Wednesday 21/10 Partly cloudy (climate normal)
+6°+1°20%
Thursday 22/10 Rain (climate normal)
+9°+3°8,4 mm
Friday 23/10 Partly cloudy (climate normal)
+8°+3°20%
Saturday 24/10 Partly cloudy (climate normal)
+13°+5°20%
Sunday 25/10 Rain (climate normal)
+11°+5°7,0 mm
Monday 26/10 Partly cloudy (climate normal)
+11°+4°20%
Tuesday 27/10 Partly cloudy (climate normal)
+10°+4°20%
Wednesday 28/10 Rain (climate normal)
+7°+2°9,2 mm
Thursday 29/10 Partly cloudy (climate normal)
+9°+4°20%
Friday 30/10 Partly cloudy (climate normal)
+9°+3°20%
Saturday 31/10 Rain (climate normal)
+11°+4°9,8 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.