Opatija weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Good
Best time to visit: June – August
What is the weather like in Opatija in September?
In September, Opatija is warm: daytime highs average 23 °C, and nights cool down to about 16 °C. The sea averages 20.8 °C – refreshing for a swim. The sun shines for around 8 hours a day. Rain is frequent, with about 10 rainy days and 166 mm in total. All in all, September is a good month for a holiday in Opatija.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 94 | 60 | 21 |
| Day | 28° | 23° | 18° |
| Night | 20° | 16° | 12° |
| Sea | 24° | 21° | 18° |
| Sun | 10 h | 8 h | 6 h |
| Rain days | 8 | 10 | 13 |
More details for September
- Daylight
- 12 h 37 min06:40 – 19:16
- UV index
- 5 · moderateclear sky, noon (estimate)All months
- Muggy days
- 1 daydew point 18 °C or moreAll months
- Wind
- 19 km/haverage daily peakAll months
- Cloud cover
- 45 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Snow days
- 0 days1 cm or more of fresh snow
- Time zone
- UTC+2Europe/Zagreb
How the score comes together
- Temperatureweight 35 %58 %
- Seaweight 25 %54 %
- Sunshineweight 20 %77 %
- Few rainy daysweight 20 %56 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in September
- Swimwear
- Sunscreen
- A jumper for the evenings
- Rain jacket or umbrella
Opatija in September: quick answers
Is Opatija hot in September?
Warm rather than hot: in September, daytime highs in Opatija average 23 °C and nights cool to about 16 °C.
Can you swim in Opatija in September?
Yes. In September the sea averages 20.8 °C – refreshing for a swim.
Does it rain much in Opatija in September?
Rain is frequent, with about 10 rainy days and 166 mm in total.
Opatija month by month
The whole year in OpatijaAll destinations: CroatiaWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences