Slovenia in September: where is it warmest?
In September, Koper is the warmest place with 22 °C by day, Bled the coolest with 19 °C. 10 of 10 destinations have good holiday weather.
All destinations in September, warmest first
Long-term averages for the month: daytime high, sea, sunshine and rainy days.
Slovenia in September: quick answers
Slovenia in September: where is it warmest?
The warmest places in September are Koper (22 °C), Piran (22 °C) and Izola (22 °C).
Slovenia in September: where is the sea warmest?
The sea is warmest at Koper (23 °C), Piran (23 °C) and Izola (23 °C).
Slovenia in September: where is the weather best?
The best holiday weather in September – warm, sunny and dry – is in Maribor, Ptuj and Celje.
Slovenia month by month
Slovenia: weather & best time to visit
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