Days 1-14 are a real forecast from global weather models. Days 15-30 are season-typical values based on Météo-France climate normals 1991-2020 — good for planning, NOT an exact forecast that far ahead.
30 days — Lille
14 real + 16 synthesised
Fri · Today Partly cloudy
+19°+14°0,2 mm
Sat · Tomorrow Clear
+22°+12°5%
Sunday 14/6 Clear
+19°+11°6%
Monday 15/6 Clear
+21°+9°5%
Tuesday 16/6 Partly cloudy
+26°+10°5%
Wednesday 17/6 Partly cloudy
+30°+16°3%
Thursday 18/6 Clear
+31°+17°2%
Friday 19/6 Partly cloudy
+23°+16°0,2 mm
Saturday 20/6 Partly cloudy
+24°+14°4%
Sunday 21/6 Showers
+33°+14°1,9 mm
Monday 22/6 Showers
+26°+17°1,2 mm
Tuesday 23/6 Partly cloudy
+21°+14°11%
Wednesday 24/6 Clear
+22°+13°6%
Thursday 25/6 Clear
+22°+11°4%
Friday 26/6 Rain (climate normal)
+21°+12°7,2 mm
Saturday 27/6 Partly cloudy (climate normal)
+23°+13°20%
Sunday 28/6 Partly cloudy (climate normal)
+22°+13°20%
Monday 29/6 Rain (climate normal)
+22°+13°4,6 mm
Tuesday 30/6 Partly cloudy (climate normal)
+21°+12°20%
Wednesday 1/7 Partly cloudy (climate normal)
+21°+13°20%
Thursday 2/7 Rain (climate normal)
+20°+12°7,2 mm
Friday 3/7 Partly cloudy (climate normal)
+25°+15°20%
Saturday 4/7 Partly cloudy (climate normal)
+25°+15°20%
Sunday 5/7 Rain (climate normal)
+25°+15°6,1 mm
Monday 6/7 Partly cloudy (climate normal)
+24°+15°20%
Tuesday 7/7 Partly cloudy (climate normal)
+21°+13°20%
Wednesday 8/7 Rain (climate normal)
+19°+12°7,2 mm
Thursday 9/7 Partly cloudy (climate normal)
+21°+13°20%
Friday 10/7 Partly cloudy (climate normal)
+22°+14°20%
Saturday 11/7 Rain (climate normal)
+24°+15°8,0 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 Météo-France climate normals 1991-2020 directly for Lille, with mild weekly variation.
Use: "Roughly how warm is it usually in Paris in the last week of July?" — a good question for days 15-30. "Will it rain on 27 May?" — no serious forecast can say.
Official weather data from Météo-France (French Meteorological and Hydrological Institute) · Météo-France · French Museum of Natural History · Bison Futé