Opatija weather in September 2026

Q: How hot is it in Opatija in September?

Daytime temperatures usually reach 25°C in Opatija in September with low heat and humidity, falling to 14°C at night.

Q: How sunny is it in Opatija in September?

There are normally 8 hours of bright sunshine each day in Opatija in September - that's 62% of daylight hours.

Q: How warm is the sea around Opatija in September?

The average sea temperature around Opatija in September is 22°C.

Q: Does it rain in Opatija in September?

There are usually 10 days with some rain in Opatija in September and the average monthly rainfall is 75mm.

Expect daytime maximum temperatures of 70°F 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 5.4 inches of rainfall in the month.

70
70°F max day temperature
7
7 hours of sunshine per day
13
13 days with some rainfall
50
50°F min night temperature
13
13 hours of daylight per day
0
No heat & humidity
5.4
5.4 inches of monthly rainfall
5
5 (Moderate) UV index
70
70°F 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) | Imperial (°F)