Click on a day for an hourly weather forecast
The temperatures in Opatija in September are comfortable with low of 13°C and and high up to 21°C.
You can expect rain for roughly half of the month of September in Opatija. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Opatija in September 2025.
If you’re planning to visit Opatija in the near future, we highly recommend that you review the 14 day weather forecast for Opatija before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 5° / -2° | 10 | 16 | 4 | 195 mm | Awful | Opatija in January |
| February | 7° / -1° | 10 | 14 | 4 | 220 mm | Awful | Opatija in February |
| March | 10° / 2° | 8 | 21 | 2 | 172 mm | Awful | Opatija in March |
| April | 15° / 7° | 8 | 22 | 0 | 143 mm | Ok | Opatija in April |
| May | 19° / 10° | 12 | 19 | 0 | 217 mm | Ok | Opatija in May |
| June | 23° / 14° | 11 | 19 | 0 | 188 mm | Good | Opatija in June |
| July | 26° / 16° | 10 | 21 | 0 | 175 mm | Good | Opatija in July |
| August | 26° / 16° | 6 | 25 | 0 | 136 mm | Perfect | Opatija in August |
| September | 21° / 13° | 8 | 22 | 0 | 198 mm | Ok | Opatija in September |
| October | 16° / 8° | 6 | 25 | 0 | 153 mm | Good | Opatija in October |
| November | 11° / 5° | 10 | 20 | 0 | 242 mm | Bad | Opatija in November |
| December | 7° / 0° | 9 | 19 | 2 | 210 mm | Awful | Opatija in December |