Portsmouth weather in September 2025

Expect 31°C daytime maximum temperatures in the shade with on average 7 hours of sunshine per day in Portsmouth in September. Check more long-term weather averages for Portsmouth in September before you book your next holiday to Dominica in 2025/2026.

  • 31°C maximum daytime temperature in September in Portsmouth31
    31°C max day temperature
  • 7 hours of sunshine per day
  • 22 days with some rainfall in September in Portsmouth22
    22 days with some rainfall
  • 24°C minimum night-time temperature in September in Portsmouth24
    24°C min night temperature
  • 12 hours of daylight per day in September in Portsmouth12
    12 hours of daylight per day
  • High heat & humidity in September in PortsmouthH
    High heat & humidity
  • 269 mm monthly rainfall in September in Portsmouth269
    269 mm of monthly rainfall
  • UV (maximum) index 11+ (Extreme) in September in Portsmouth11
    11+ (Extreme) UV index
  • 29°C sea temperature in September in Portsmouth29
    29°C sea temperature

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The September weather guide for Dominica (Portsmouth) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C / mm)  |  Imperial (°F / inches)

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How hot is it in Portsmouth in September?

Daytime temperatures usually reach 31°C in Portsmouth in September with high heat and humidity, falling to 24°C at night.

How sunny is it in Portsmouth in September?

There are normally 7 hours of bright sunshine each day in Portsmouth in September - that's 58% of daylight hours.

How warm is the sea around Portsmouth in September?

The average sea temperature around Portsmouth in September is 29°C.

Does it rain in Portsmouth in September?

There are usually 22 days with some rain in Portsmouth in September and the average monthly rainfall is 269mm.

What is the chance of a hurricane in Portsmouth in September?

On average 1.2 days in September in Portsmouth are likely to be affected by the passage of one or more tropical storms.

Portsmouth September sunrise & sunset times

Browse the sunrise and sunset times for Portsmouth in September 2025. Select a month to view Portsmouth sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:53 18:18
Monday, 15th September 2025 05:54 18:07
Tuesday, 30th September 2025 05:56 17:56

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