Climate averages 1991–2020
Trieste weather
in September.
A warm, wet month: the 4th warmest and the 10th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Trieste: daytime highs average 22.3°C and nights cool to about 14.8°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 170 mm of rain on roughly 11 days, which makes September a wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 35 min on an average September day.
The nearest other city in this atlas is Udine (63 km away). In September its highs average 21.4°C, 0.9°C cooler than Trieste, with 153 mm of rain.
Among the 79 cities listed in Italy, Trieste ranks 69th of 79 for the warmest September highs and 79th of 79 for the driest September (rainfall, lowest first). The mean September high of those 79 cities is 24.3°C; Trieste is 2.0°C cooler than that mean.
From September to October, average highs fall by 4.9°C to 17.4°C, and monthly rainfall rises from 170 mm to 184 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
Trieste climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.2°C1.1°C | 1.1°C | 90 | 9.5 | 9.19 h |
| February | 8.6°C1.1°C | 1.1°C | 97 | 8.7 | 10.310 h |
| March | 12.4°C4.1°C | 4.1°C | 101 | 9.7 | 11.912 h |
| April | 16.4°C7.8°C | 7.8°C | 110 | 12.1 | 13.513 h |
| May | 20.6°C12.3°C | 12.3°C | 122 | 13.0 | 14.915 h |
| June | 24.8°C16.4°C | 16.4°C | 111 | 12.1 | 15.616 h |
| July | 27.4°C18.7°C | 18.7°C | 87 | 10.7 | 15.315 h |
| August | 27.7°C18.9°C | 18.9°C | 111 | 10.2 | 14.114 h |
| September, selected | 22.3°C14.8°C | 14.8°C | 170 | 11.4 | 12.613 h |
| October | 17.4°C10.8°C | 10.8°C | 184 | 13.0 | 11.011 h |
| November | 12.3°C6.5°C | 6.5°C | 195 | 13.2 | 9.510 h |
| December | 8.0°C2.0°C | 2.0°C | 129 | 10.1 | 8.89 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
- Udine in SeptemberItaly · 63 kmHigh 21.4°C · Low 12.3°C · 153 mm rain
- Rijeka in SeptemberCroatia · 63 kmHigh 22.3°C · Low 14.8°C · 177 mm rain
- Ljubljana in SeptemberSlovenia · 72 kmHigh 19.8°C · Low 11.5°C · 125 mm rain
- Klagenfurt am Wörthersee in SeptemberAustria · 116 kmHigh 19.2°C · Low 11.1°C · 139 mm rain
- Treviso in SeptemberItaly · 119 kmHigh 22.8°C · Low 14.0°C · 120 mm rain
- Mestre in SeptemberItaly · 120 kmHigh 23.0°C · Low 15.5°C · 123 mm rain
- Padua in SeptemberItaly · 150 kmHigh 23.6°C · Low 14.8°C · 107 mm rain
- Zagreb in SeptemberCroatia · 172 kmHigh 21.8°C · Low 12.6°C · 94 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 Trieste) is explained once on the Trieste year overview and on the Sources, method and limits page.