30-day forecast · Southampton

Days 1-14 are a real forecast from weather models. Days 15-30 are season-typical values based on 1991-2020 climate averages — good for planning, NOT an exact forecast that far ahead.

30 days — Southampton

14 real + 16 synthesised

Thu · Today Sunny intervals

24° 14° 0.8 mm

Fri · Tomorrow Sunny

25° 12° 1%

Saturday 1/8 Sunny

24° 10° 2%

Sunday 2/8 Sunny intervals

26° 12° 3%

Monday 3/8 Sunny

30° 15° 5%

Tuesday 4/8 Sunny intervals

27° 15° 6%

Wednesday 5/8 Sunny

25° 17° 0.5 mm

Thursday 6/8 Sunny

29° 15° 17%

Friday 7/8 Sunny intervals

24° 17° 18%

Saturday 8/8 Sunny intervals

23° 17° 20%

Sunday 9/8 Sunny intervals

27° 18° 19%

Monday 10/8 Sunny

28° 15° 4%

Tuesday 11/8 Sunny

29° 17° 4%

Wednesday 12/8 Sunny

25° 16° 4%

Thursday 13/8 Rain (climate average)

30° 20° 5.7 mm

Friday 14/8 Sunny intervals (climate average)

31° 21° 20%

Saturday 15/8 Sunny intervals (climate average)

32° 22° 20%

Sunday 16/8 Rain (climate average)

32° 21° 4.2 mm

Monday 17/8 Sunny intervals (climate average)

29° 19° 20%

Tuesday 18/8 Sunny intervals (climate average)

29° 20° 20%

Wednesday 19/8 Rain (climate average)

28° 19° 6.8 mm

Thursday 20/8 Sunny intervals (climate average)

31° 21° 20%

Friday 21/8 Sunny intervals (climate average)

33° 22° 20%

Saturday 22/8 Rain (climate average)

31° 21° 3.7 mm

Sunday 23/8 Sunny intervals (climate average)

31° 21° 20%

Monday 24/8 Sunny intervals (climate average)

29° 20° 20%

Tuesday 25/8 Rain (climate average)

27° 18° 4.2 mm

Wednesday 26/8 Sunny intervals (climate average)

27° 19° 20%

Thursday 27/8 Sunny intervals (climate average)

30° 20° 20%

Friday 28/8 Rain (climate average)

34° 22° 5.7 mm

How does the long-range forecast work?

Days 1-14: Fetched live from weather models (UKV, 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 max/min from 1991-2020 climate data (London baseline with latitude correction for Southampton), with mild weekly variation.

Use: "Roughly how warm is it usually in London in the last week of July?" — a good question for days 15-30. "Will it rain on 27 May?" — no serious forecast can say.

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