Cascais weather in September 2025

Expect 26°C daytime maximum temperatures in the shade with on average 8 hours of sunshine per day in Cascais in September. Check more long-term weather averages for Cascais in September before you book your next holiday to Portugal in 2025/2026.

  • 26°C maximum daytime temperature in September in Cascais26
    26°C max day temperature
  • 8 hours of sunshine per day
  • 6 days with some rainfall in September in Cascais6
    6 days with some rainfall
  • 17°C minimum night-time temperature in September in Cascais17
    17°C min night temperature
  • 12 hours of daylight per day in September in Cascais12
    12 hours of daylight per day
  • No heat & humidity in September in Cascais0
    No heat & humidity
  • 31 mm monthly rainfall in September in Cascais31
    31 mm of monthly rainfall
  • UV (maximum) index 6 (High) in September in Cascais6
    6 (High) UV index
  • 19°C sea temperature in September in Cascais19
    19°C sea temperature

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The September weather guide for Portugal (Cascais) 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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More about Portugal

How hot is it in Cascais in September?

Daytime temperatures usually reach 26°C in Cascais in September with no heat and humidity, falling to 17°C at night.

How sunny is it in Cascais in September?

There are normally 8 hours of bright sunshine each day in Cascais in September - that's 68% of daylight hours.

How warm is the sea around Cascais in September?

The average sea temperature around Cascais in September is 19°C.

Does it rain in Cascais in September?

There are usually 6 days with some rain in Cascais in September and the average monthly rainfall is 31mm.

Cascais September sunrise & sunset times

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

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 06:07 19:08
Monday, 15th September 2025 06:19 18:46
Tuesday, 30th September 2025 06:33 18:22

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