Trieste weather in September
September in Trieste: nice, soaked, with clean air — fine if you can take 10 rainy days.
#1 of 12 months in Trieste · #267 of 897 destinations to visit in September · comfort 88/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Traveller notes on Trieste in September
No notes yet. Open Trieste on the map to add the first one.
Trieste climate normals — September
| Daytime high | 24°C / 75°F | 😎 nice |
|---|---|---|
| Nighttime low | 16°C / 61°F | |
| Rainfall | 169 mm / 6.7 in | ⛈ soaked |
| Rainy days | 10 days | |
| Humidity | 75% | 💧 humid |
| Dew point | 15°C / 59°F | |
| Sunshine | 10 h/day | |
| Daylight | 12.5 h | |
| Wind | 15 km/h / 10 mph | |
| Air quality (US AQI) | 44 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Trieste?
Loading map…
Trieste in September — FAQ
- Is September a good time to visit Trieste?
- September in Trieste: nice, soaked, with clean air — fine if you can take 10 rainy days. It ranks #1 of 12 months for Trieste on SeasonMap's comfort score (88/100).
- What is the weather like in Trieste in September?
- In September, Trieste averages a daily high of 23.8°C and a low of 16°C, with about 169 mm of rain over roughly 9.8 rainy days.
- What is the air quality in Trieste in September?
- Trieste has a mean US Air Quality Index of about 44 in September.