Trieste sits on the Adriatic Sea in northeastern Italy and has a humid subtropical climate (Cfa) with strong Mediterranean influences. July and August are warm and sunny, averaging 28°C (82°F), while January dips to 4°C (39°F). The city gets about 1,000mm of rain per year spread across 90 rain days, with October and November the wettest months. Trieste’s defining weather feature is the Bora wind, a powerful katabatic wind that funnels down from the Karst plateau, reaching gusts of 150 km/h (93 mph). The Bora is most common from November through March and can drop temperatures by 10°C in hours.
Trieste Weather by Month: Temperature and Rainfall Breakdown
| Month | Avg High | Avg Low | Rain (mm) | Rain Days | Sea Temp | Sun Hours |
|---|---|---|---|---|---|---|
| January | 8°C (46°F) | 4°C (39°F) | 71 | 7 | 10°C (50°F) | 4 |
| February | 9°C (48°F) | 4°C (39°F) | 62 | 6 | 9°C (48°F) | 5 |
| March | 13°C (55°F) | 7°C (45°F) | 77 | 7 | 10°C (50°F) | 5 |
| April | 17°C (63°F) | 10°C (50°F) | 87 | 9 | 13°C (55°F) | 6 |
| May | 22°C (72°F) | 14°C (57°F) | 81 | 9 | 17°C (63°F) | 8 |
| June | 26°C (79°F) | 18°C (64°F) | 102 | 9 | 22°C (72°F) | 9 |
| July | 28°C (82°F) | 20°C (68°F) | 71 | 7 | 25°C (77°F) | 10 |
| August | 28°C (82°F) | 20°C (68°F) | 101 | 7 | 25°C (77°F) | 9 |
| September | 24°C (75°F) | 16°C (61°F) | 138 | 8 | 22°C (72°F) | 7 |
| October | 19°C (66°F) | 12°C (54°F) | 147 | 9 | 19°C (66°F) | 5 |
| November | 13°C (55°F) | 8°C (46°F) | 138 | 9 | 16°C (61°F) | 3 |
| December | 9°C (48°F) | 5°C (41°F) | 99 | 8 | 12°C (54°F) | 3 |
Trieste Weather by Month: Winter (December to February)
Winter in Trieste is cold and windy but rarely drops below freezing at sea level. Daytime highs hover around 8 to 9°C (46 to 48°F), with overnight lows of 4 to 5°C (39 to 41°F). Snow is uncommon in the city, Trieste averages 1 to 2 snow days per year, but the nearby Carso plateau gets regular dustings. The Bora wind defines winter here: when it blows, wind chill makes 8°C feel closer to -3°C (27°F). December brings about 8 rain days and just 3 hours of daily sunshine. January is the coldest month with sea temperatures dropping to 10°C (50°F). February sees slightly more sun but remains windy.
Trieste Weather by Month: Spring (March to May)
Spring starts cool but improves steadily. March averages 13°C (55°F) with 7 rain days and the Bora still making regular appearances. By April, highs reach 17°C (63°F) and the city’s outdoor cafes on Piazza Unita d’Italia start filling up. May is the driest spring month with 9 rain days but less total rainfall, and temperatures hit 22°C (72°F), warm enough for al fresco dining along the Canal Grande. The sea warms from 10°C (50°F) in March to 17°C (63°F) in May. Sunshine jumps from 5 hours in March to 8 in May.
Trieste Weather by Month: Summer (June to August)
Summer is Trieste’s peak season. June brings 26°C (79°F) highs and 18°C (64°F) lows with 9 hours of daily sun. July and August are the warmest at 28°C (82°F), with overnight lows of 20°C (68°F). Humidity averages 65%, making the heat feel manageable rather than oppressive. Thunderstorms are common in June and August, expect 7 to 9 rain days each month, often as short afternoon downpours that clear quickly. The Adriatic reaches 25°C (77°F) in July and August, warm enough for swimming at Barcola beach. The Bora is almost absent in summer, replaced by light Maestral breezes.
Trieste Weather by Month: Autumn (September to November)
September starts warm at 24°C (75°F) but is Trieste’s second-wettest month with 138mm of rain across 8 days. The sea stays pleasant at 22°C (72°F) through early October. October is the wettest month (147mm, 9 rain days) with highs dropping to 19°C (66°F). November marks the Bora’s return, temperatures fall to 13°C (55°F) highs and 8°C (46°F) lows, and the month sees 138mm of rain plus frequent gale-force winds. Sunshine drops to just 3 hours daily in November.
Trieste Weather by Month: Understanding the Bora Wind
The Bora is a cold, dry katabatic wind that descends from the Karst plateau northeast of Trieste. It can gust from 100 to 170 km/h (62 to 106 mph) and lasts anywhere from a few hours to several days. The wind is strongest near the port and along the waterfront, chains are sometimes installed on Piazza Unita d’Italia railings during severe events so pedestrians can hold on. Bora days are most frequent from November through March, peaking in January and February with 8 to 12 Bora days per month. In summer, the Bora appears only 1 to 2 days per month. The wind brings clear skies and excellent visibility when it blows, perfect for photography but unpleasant for walking.
Explore more of our Trieste guides: best time to visit Trieste, Trieste events and festivals, Trieste neighborhoods guide, things to do in Trieste, Trieste travel tips, and where to stay in Trieste. For a complete overview, see our Trieste travel guide.
