Mild
Average highs are around 21°C, so days are mild rather than hot.
September verdict
Opatija, Croatia in September
Weather score43Mixed
Mixed for holiday weather
Average highs are around 21°C, so days are mild rather than hot. Sunshine averages 6.7h per day, enough for a balanced month. Rainfall averages 138mm, so some wet days are possible.
September weather
Monthly averages
Temp
21°C
Rain
138mm
Sun
6.7h
Sea
20°C
Weather score
43
Mixed
Seasonal climate calendar
TemperatureTemp
RainRain
SunSun
SwimSwim
Weather scoreWeather score
Trip feel
Showers
Rainfall averages 138mm, so some wet days are possible.
Some sun
Sunshine averages 6.7h per day, enough for a balanced month.
Cool sea
Sea temperatures average 20°C, so the water can feel cool.
Map
Weather map
Compare Opatija, Croatia with nearby places by weather score, rain, sun, temperature, and swim conditions.
Temperature
September21°C average high
September sits in the warmer part of the year, so midday sightseeing can feel heavier than in cooler months.
Warmest monthsJune to September
This stretch sets the upper range for average daytime heat.
Rain
September138mm average rain
September sits near Opatija's yearly rainfall average, so rain is a normal planning factor rather than an outlier.
Driest monthsJanuary to August
This is the drier part of the year, when outdoor plans usually need less weather flexibility.
Sun
September6.7 hours average sun
September sits close to Opatija's yearly sunshine average, so it is a middle-of-the-pack month for bright days.
Brightest monthsJune to August
This stretch has the strongest sunshine in the monthly averages.
Sea temperature
September20°C average sea
September sits in the warmer sea-temperature season, usually making swimming easier to enjoy.
Warmest seaJune to September
Sea temperatures are usually near 21°C in this stretch, so swimming comfort is at its strongest.
Weather score
September43 weather score
September sits close to Opatija's yearly weather-score average, giving a typical overall read on the month.
Best weather monthsJuly to August
These months have the strongest weather score in the monthly averages.
