Climate averages 1991–2020
Ljubljana weather
in September.
A mild, wet month: the 4th warmest and the wettest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Ljubljana: daytime highs average 19.8°C and nights cool to about 11.5°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 125 mm of rain on roughly 11 days, which makes September a wet month (the wettest month of the year). Daylight, from sunrise to sunset, lasts about 12 h 36 min on an average September day.
The nearest other city in this atlas is Klagenfurt am Wörthersee (66 km away). In September its highs average 19.2°C, 0.6°C cooler than Ljubljana, with 139 mm of rain.
Among the 2 cities listed in Slovenia, Ljubljana ranks 2nd of 2 for the warmest September highs and 2nd of 2 for the driest September (rainfall, lowest first). The mean September high of those 2 cities is 20.2°C; Ljubljana is 0.4°C cooler than that mean.
From September to October, average highs fall by 5.2°C to 14.6°C, and monthly rainfall falls from 125 mm to 117 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Ljubljana climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 3.7°C-2.7°C | -2.7°C | 59 | 8.0 | 9.19 h |
| February | 5.7°C-2.3°C | -2.3°C | 75 | 8.5 | 10.310 h |
| March | 10.3°C1.3°C | 1.3°C | 76 | 10.1 | 11.912 h |
| April | 15.1°C5.3°C | 5.3°C | 90 | 12.0 | 13.514 h |
| May | 19.3°C9.7°C | 9.7°C | 103 | 13.4 | 14.915 h |
| June | 23.2°C13.6°C | 13.6°C | 105 | 13.4 | 15.716 h |
| July | 25.3°C15.8°C | 15.8°C | 95 | 11.3 | 15.415 h |
| August | 25.2°C15.9°C | 15.9°C | 112 | 11.1 | 14.214 h |
| September, selected | 19.8°C11.5°C | 11.5°C | 125 | 11.1 | 12.613 h |
| October | 14.6°C7.3°C | 7.3°C | 117 | 10.2 | 11.011 h |
| November | 9.1°C3.1°C | 3.1°C | 121 | 11.2 | 9.510 h |
| December | 4.3°C-1.9°C | -1.9°C | 90 | 9.2 | 8.79 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Klagenfurt am Wörthersee in SeptemberAustria · 66 kmHigh 19.2°C · Low 11.1°C · 139 mm rain
- Trieste in SeptemberItaly · 72 kmHigh 22.3°C · Low 14.8°C · 170 mm rain
- Rijeka in SeptemberCroatia · 81 kmHigh 22.3°C · Low 14.8°C · 177 mm rain
- Udine in SeptemberItaly · 98 kmHigh 21.4°C · Low 12.3°C · 153 mm rain
- Maribor in SeptemberSlovenia · 104 kmHigh 20.5°C · Low 11.9°C · 111 mm rain
- Zagreb in SeptemberCroatia · 117 kmHigh 21.8°C · Low 12.6°C · 94 mm rain
- Graz in SeptemberAustria · 134 kmHigh 19.2°C · Low 9.7°C · 83 mm rain
- Bihać in SeptemberBosnia and Herzegovina · 174 kmHigh 21.6°C · Low 12.4°C · 124 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Ljubljana) is explained once on the Ljubljana year overview and on the Sources, method and limits page.