Click on a day for an hourly weather forecast
The temperatures in Portoroz in September are comfortable with low of 15°C and and high up to 24°C.
You can expect rain for roughly half of the month of September in Portoroz. 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 Portoroz in September 2025.
If you’re planning to visit Portoroz in the near future, we highly recommend that you review the 14 day weather forecast for Portoroz before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 7° / 0° | 8 | 22 | 2 | 154 mm | Awful | Portoroz in January |
| February | 9° / 1° | 8 | 18 | 2 | 204 mm | Awful | Portoroz in February |
| March | 12° / 3° | 8 | 22 | 1 | 161 mm | Bad | Portoroz in March |
| April | 17° / 8° | 7 | 23 | 0 | 143 mm | Ok | Portoroz in April |
| May | 21° / 11° | 11 | 20 | 0 | 219 mm | Ok | Portoroz in May |
| June | 26° / 16° | 9 | 21 | 0 | 192 mm | Good | Portoroz in June |
| July | 28° / 19° | 7 | 24 | 0 | 155 mm | Good | Portoroz in July |
| August | 29° / 20° | 6 | 25 | 0 | 138 mm | Good | Portoroz in August |
| September | 24° / 15° | 9 | 21 | 0 | 240 mm | Good | Portoroz in September |
| October | 18° / 10° | 7 | 24 | 0 | 198 mm | Ok | Portoroz in October |
| November | 13° / 6° | 10 | 20 | 0 | 272 mm | Bad | Portoroz in November |
| December | 9° / 2° | 8 | 22 | 1 | 224 mm | Bad | Portoroz in December |