Opatija weather in September 2025

Expect daytime maximum temperatures of 21°C in Opatija, Croatia in September based on long-term weather averages. There are 7 hours of sunshine per day on average with 13 days with some rainfall and typically 138 mm of rainfall in the month.

  • 21°C maximum daytime temperature in September in Opatija21
    21°C max day temperature
  • 7 hours of sunshine per day
  • 13 days with some rainfall in September in Opatija13
    13 days with some rainfall
  • 10°C minimum night-time temperature in September in Opatija10
    10°C min night temperature
  • 13 hours of daylight per day in September in Opatija13
    13 hours of daylight per day
  • No heat & humidity in September in Opatija0
    No heat & humidity
  • 138 mm monthly rainfall in September in Opatija138
    138 mm of monthly rainfall
  • UV (maximum) index 5 (Moderate) in September in Opatija5
    5 (Moderate) UV index
  • 21°C sea temperature in September in Opatija21
    21°C sea temperature

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The September weather guide for Croatia (Opatija) 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 Croatia

How hot is it in Opatija in September?

Daytime temperatures usually reach 21°C in Opatija in September, falling to 10°C at night.

How sunny is it in Opatija in September?

There are normally 7 hours of bright sunshine each day in Opatija in September - that's 53% of daylight hours.

How warm is the sea around Opatija in September?

The average sea temperature around Opatija in September is 21°C.

Does it rain in Opatija in September?

There are usually 13 days with some rain in Opatija in September and the average monthly rainfall is 138mm.

Opatija September sunrise & sunset times

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

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:24 18:40
Monday, 15th September 2025 05:41 18:14
Tuesday, 30th September 2025 06:00 17:45

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