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The temperatures in Slovenia in September are quite cold with temperatures between 9°C and 20°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Slovenia during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Slovenia in September 2025.
If you’re planning to visit Slovenia in the near future, we highly recommend that you review the 14 day weather forecast for Slovenia before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 2° / -4° | 6 | 15 | 10 | 102 mm | Awful | Slovenia in January |
| February | 4° / -3° | 6 | 13 | 9 | 141 mm | Awful | Slovenia in February |
| March | 9° / 1° | 6 | 22 | 4 | 112 mm | Bad | Slovenia in March |
| April | 15° / 4° | 6 | 23 | 1 | 106 mm | Good | Slovenia in April |
| May | 20° / 8° | 9 | 22 | 0 | 174 mm | Ok | Slovenia in May |
| June | 25° / 11° | 8 | 22 | 0 | 148 mm | Good | Slovenia in June |
| July | 27° / 13° | 7 | 24 | 0 | 156 mm | Good | Slovenia in July |
| August | 26° / 13° | 6 | 25 | 0 | 127 mm | Perfect | Slovenia in August |
| September | 20° / 9° | 6 | 24 | 0 | 158 mm | Good | Slovenia in September |
| October | 14° / 6° | 5 | 26 | 0 | 118 mm | Good | Slovenia in October |
| November | 9° / 3° | 7 | 21 | 1 | 153 mm | Bad | Slovenia in November |
| December | 4° / -2° | 6 | 19 | 6 | 125 mm | Awful | Slovenia in December |