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