Climate - Trieste (Italy)

Trieste: Temperatures - Precipitation - Sunshine hours - Sea temperatures - Best time - Weather by month


The climate of Trieste can be described as transitional Mediterranean.
The city is located in the north-east of Italy and is the capital of the Friuli-Venezia Giulia region.
Being on the coast and outside of the Po Valley, it has a relatively mild climate. However, this city is particularly subject to the Bora,the wind that is channeled through the mountain ranges when cold air masses arrive from eastern Europe. So, the wind rushes to the Gulf of Trieste, with gusts above 100 kilometers (60 miles) per hour, and can also lower the temperature below freezing from December to early March.
The average temperature of the coldest month (January) is of 6.5 °C (43.5 °F), that of the warmest months (July and August) is of 25 °C (77 °F). Here are the average temperatures.

Trieste is a quite rainy city: 1,000 mm (40 in) of rain fall in a typical year, and there can be thunderstorms in late spring and summer. Precipitation ranges from 55 mm (2.2 in) in the driest month (February) to 110 mm (4.3 in) in the wettest (October). Here is the average precipitation.

The winter, from December to February or early March, is quite mild, and is characterized by sunny periods alternating with rainy periods.
There are also cold periods, in which the bora blows and the temperature drops to around freezing even during the day.
During the most intense cold spells, the temperature can drop as low as -7 °C (19.5 °F), and can remain below freezing even during the day, as happened for example in January 1985, February 1991, December 1996 and February 2012. However, in the past, the temperature had dropped to -10.5 °C (13 °F) in February 1956 and to -9.5 °C (15 °F) in January 1963.
Even if the temperatures do not reach the values of the Po Valley, the wind increases the sensation of cold. For example, with a wind of 100 kph (60 mph), if the air temperature is 0 °C (32 °F), the perceived temperature (wind chill) will be -10.5 °C (13 °F), while if the air temperature is -5 °C (23 °F), the perceived temperature will be -18 °C (-0.5 °F).
Snow in Trieste is rare because the Bora is originally a dry wind, though sometimes its rarer version, called "dark Bora", can bring some light snowfalls. On average, less than 10 cm (4 in) fall per year. On the other hand, when the wind blows from the sea, the temperature is mild and therefore rain falls instead of snow.



Summer is hot and humid, but tempered by the breezes.
The sun often shines, but some rain or thunderstorms can sometimes occur.
During heat waves, which are becoming increasingly more frequent, the temperature can reach or exceed 35 °C (95 °F). The heat record is 38 °C (100.5 °F) and was recorded in the months of August 2015 and 2017. The temperature of 37 °C recorded in late June 2019 and in August 2003 are also worth mentioning.



On average, there are around 2,110 sunshine hours per year. Here are the average sunshine hours per day.

The sea temperature ranges between 10 °C (50 °F) and 26 °C (79 °F). The sea is warm enough for swimming from July to September. Here are the average sea temperatures.

Best Time

The best periods to visit Trieste are spring and autumn, and in particular, from mid-April to mid-June and in the month of September. However, in both periods, some rainy days are possible. The best months to go to the beach are July and August. In June, the sea is still a little cool.

Trieste - Weather by month

Based on the period 1991-2020

---

In January, the coldest month of the year, the weather in Trieste is usually quite cold. The average temperature is of 6.5 °C (44 °F), with a minimum of 4.1 °C (39.4 °F) and a maximum of 8.9 °C (48 °F).
On the coldest nights of the month, the temperature usually drops to around -1.5 °C (29 °F). However, it dropped to -7 °C (19.4 °F) in January 2017.
On the warmest days of the month, the temperature usually reaches around 14 °C (57.5 °F). However, it reached 18.2 °C (64.8 °F) in January 2018.
Precipitation amounts to 60 mm (2.4 in), distributed over 7 days.
The day lasts on average 9 hours and 10 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 34% of the time.
The average humidity is 67%.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 11.5 °C (53 °F). Therefore, the sea is very cold for swimming.

---

In February, the weather in Trieste is usually quite mild. The average temperature is of 6.8 °C (44 °F), with a minimum of 4.1 °C (39.5 °F) and a maximum of 9.5 °C (49.1 °F).
On the coldest nights of the month, the temperature usually drops to around -1 °C (30 °F). However, it dropped to -7.2 °C (19 °F) in February 2012.
On the warmest days of the month, the temperature usually reaches around 15 °C (59 °F). However, it reached 18.2 °C (64.8 °F) in February 2001.
Precipitation amounts to 55 mm (2.2 in), distributed over 6 days.
The day lasts on average 10 hours and 25 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 40% of the time.
The average humidity is 64%.
The average wind speed is 10 kph (6 mph).
The average sea temperature is of 10.5 °C (50.5 °F). Therefore, the sea is very cold for swimming.

---

In March, the weather in Trieste is usually mild. The average temperature is of 10.3 °C (50 °F), with a minimum of 7 °C (44.7 °F) and a maximum of 13.5 °C (56.2 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 2 °C (35.5 °F). However, it dropped to -6.4 °C (20.5 °F) in March 2005.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 19.5 °C (67 °F). However, it reached 24 °C (75.2 °F) in March 2019.
Precipitation amounts to 65 mm (2.6 in), distributed over 7 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 4.5 hours of sunshine per day. So, the sun shines 38% of the time.
The average humidity is 62%.
The average wind speed is 9 kph (5 mph).
The average sea temperature is of 11 °C (52 °F). Therefore, the sea is very cold for swimming.

---

In April, the weather in Trieste is usually mild. The average temperature is of 14.1 °C (57 °F), with a minimum of 10.6 °C (51.1 °F) and a maximum of 17.6 °C (63.7 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 5 °C (41.5 °F). However, it dropped to 1.3 °C (34.3 °F) in April 2003.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 24 °C (75 °F). However, it reached 29.8 °C (85.6 °F) in April 2012.
Precipitation amounts to 85 mm (3.3 in), distributed over 8 days.
The day lasts on average 13 hours and 35 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 63%.
The average wind speed is 7 kph (5 mph).
The average sea temperature is of 13.5 °C (56.5 °F). Therefore, the sea is very cold for swimming.

---

In May, the weather in Trieste is usually warm. The average temperature is of 18.6 °C (65 °F), with a minimum of 14.8 °C (58.7 °F) and a maximum of 22.3 °C (72.1 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 10 °C (50 °F). However, it dropped to 7 °C (44.6 °F) in May 1997.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 28 °C (82 °F). However, it reached 32.2 °C (90 °F) in May 2003.
Precipitation amounts to 85 mm (3.3 in), distributed over 9 days.
The day lasts on average 15 hours and 0 minutes. So the days are long.
There are on average 7.5 hours of sunshine per day. So, the sun shines 49% of the time.
The average humidity is 63%.
The average wind speed is 7 kph (4 mph).
The average sea temperature is of 18 °C (64.5 °F). Therefore, the sea is cold for swimming.

---

In June, the weather in Trieste is usually warm to hot. The average temperature is of 22.7 °C (73 °F), with a minimum of 18.8 °C (65.9 °F) and a maximum of 26.5 °C (79.7 °F).
On the coldest nights, which normally occur at the beginning of the month, the temperature usually drops to around 13 °C (55 °F). However, it dropped to 9.2 °C (48.6 °F) in June 2006.
On the warmest days, which normally occur at the end of the month, the temperature usually reaches around 32 °C (90 °F). However, it reached 36.8 °C (98.2 °F) in June 2019.
Precipitation amounts to 100 mm (3.9 in), distributed over 9 days.
The day lasts on average 15 hours and 35 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 8 hours of sunshine per day. So, the sun shines 52% of the time.
The average humidity is 63%.
The average wind speed is 7 kph (4 mph).
The average sea temperature is of 22.5 °C (72.5 °F). Therefore, the sea can be considered barely acceptable for swimming.

---

In July, the weather in Trieste is usually warm to hot. The average temperature is of 25.0 °C (77 °F), with a minimum of 21 °C (69.8 °F) and a maximum of 29.1 °C (84.4 °F).
On the coldest nights of the month, the temperature usually drops to around 15.5 °C (60 °F). However, it dropped to 13.2 °C (55.8 °F) in July 2007.
On the warmest days of the month, the temperature usually reaches around 34 °C (93.5 °F). However, it reached 37.6 °C (99.7 °F) in July 2012.
Precipitation amounts to 60 mm (2.4 in), distributed over 6 days.
The day lasts on average 15 hours and 20 minutes. So the days are long.
There are on average 9.5 hours of sunshine per day. So, the sun shines 61% of the time.
The average humidity is 61%.
The average wind speed is 7 kph (4 mph).
The average sea temperature is of 25 °C (77 °F). Therefore, the sea is warm enough for swimming.

---

In August, the hottest month of the year, the weather in Trieste is usually warm to hot. The average temperature is of 25.1 °C (77 °F), with a minimum of 21.2 °C (70.2 °F) and a maximum of 29 °C (84.2 °F).
On the coldest nights of the month, the temperature usually drops to around 16 °C (60.5 °F). However, it dropped to 11 °C (51.8 °F) in August 1995.
On the warmest days of the month, the temperature usually reaches around 33.5 °C (92.5 °F). However, it reached 38 °C (100.4 °F) in August 2017.
Precipitation amounts to 85 mm (3.3 in), distributed over 6 days.
The day lasts on average 14 hours and 0 minutes.
There are on average 8.5 hours of sunshine per day. So, the sun shines 60% of the time.
The average humidity is 61%.
The average wind speed is 7 kph (5 mph).
The average sea temperature is of 25.5 °C (78 °F). Therefore, the sea is warm enough for swimming.

---

In September, the weather in Trieste is usually warm. The average temperature is of 20.7 °C (69 °F), with a minimum of 17.1 °C (62.8 °F) and a maximum of 24.2 °C (75.6 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 12 °C (54 °F). However, it dropped to 9.2 °C (48.6 °F) in September 2001.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 29 °C (84.5 °F). However, it reached 33.8 °C (92.8 °F) in September 2016.
Precipitation amounts to 105 mm (4.1 in), distributed over 8 days.
The day lasts on average 12 hours and 30 minutes.
There are on average 7 hours of sunshine per day. So, the sun shines 56% of the time.
The average humidity is 63%.
The average wind speed is 9 kph (5 mph).
The average sea temperature is of 23 °C (73.5 °F). Therefore, the sea can be considered barely acceptable for swimming.

---

In October, the weather in Trieste is usually very mild. The average temperature is of 16.1 °C (61 °F), with a minimum of 13.2 °C (55.7 °F) and a maximum of 19 °C (66.2 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 7.5 °C (45 °F). However, it dropped to 3.8 °C (38.8 °F) in October 2003.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 24 °C (75.5 °F). However, it reached 30.8 °C (87.4 °F) in October 2011.
Precipitation amounts to 110 mm (4.3 in), distributed over 9 days.
The day lasts on average 10 hours and 55 minutes.
There are on average 5.5 hours of sunshine per day. So, the sun shines 49% of the time.
The average humidity is 68%.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 19.5 °C (67.5 °F). Therefore, the sea is very cool for swimming.

---

In November, the weather in Trieste is usually mild. The average temperature is of 11.7 °C (53 °F), with a minimum of 9.2 °C (48.5 °F) and a maximum of 14.2 °C (57.6 °F).
On the coldest nights, which normally occur at the end of the month, the temperature usually drops to around 3 °C (37.5 °F). However, it dropped to -1.3 °C (29.7 °F) in November 1993.
On the warmest days, which normally occur at the beginning of the month, the temperature usually reaches around 20 °C (68 °F). However, it reached 24.4 °C (75.9 °F) in November 2004.
Precipitation amounts to 105 mm (4.1 in), distributed over 9 days.
The day lasts on average 9 hours and 30 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 35% of the time.
The average humidity is 70%.
The average wind speed is 9 kph (6 mph).
The average sea temperature is of 16.5 °C (61.5 °F). Therefore, the sea is cold for swimming.

---

In December, the weather in Trieste is usually quite mild. The average temperature is of 7.7 °C (46 °F), with a minimum of 5.2 °C (41.3 °F) and a maximum of 10.2 °C (50.3 °F).
On the coldest nights of the month, the temperature usually drops to around -1 °C (30.5 °F). However, it dropped to -7.2 °C (19 °F) in December 1996.
On the warmest days of the month, the temperature usually reaches around 15.5 °C (60 °F). However, it reached 18.4 °C (65.1 °F) in December 2016.
Precipitation amounts to 90 mm (3.5 in), distributed over 8 days.
The day lasts on average 8 hours and 50 minutes. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 2.5 hours of sunshine per day. So, the sun shines 31% of the time.
The average humidity is 66%.
The average wind speed is 11 kph (7 mph).
The average sea temperature is of 14 °C (57 °F). Therefore, the sea is very cold for swimming.