Last updated: March 24, 2025
September in Trieste, Italy, offers a delightful transition from the warmth of summer to the cool embrace of autumn. With maximum temperatures reaching 30°C (87°F) and an average of 19°C (66°F), the weather remains pleasantly warm, making it ideal for outdoor activities and sightseeing. However, visitors should be prepared for occasional rain, as the city experiences about 183 mm (7.2 in) of precipitation over 12 days throughout the month. Humidity levels hover around 64%, adding a touch of freshness to the air. Whether strolling along the coastline or exploring the city’s rich history, September in Trieste is a magnificent time to experience this charming destination.
In September, Trieste, Italy transitions into early autumn, showcasing a delightful blend of summer warmth and a hint of cooler air. With temperatures ranging from a mild 8°C (46°F) at night to a pleasant 30°C (87°F) during the day, this month offers comfortable conditions perfect for exploring the city. The average temperature settles around 19°C (66°F), reflecting a significant dip from the scorching heights of August while still embracing the residual summer charm. As September progresses, days gradually shorten and the air feels fresher, inviting both locals and visitors to savor the picturesque coastal views and historical sites before the chill of autumn sets in.
September marks a notable shift in Trieste's weather, bringing an impressive 183 mm (7.2 in) of precipitation over 12 days. This significant rainfall is a marked increase from the drier summer months, such as August, which only saw 89 mm (3.5 in) across 10 days. The surge in precipitation in September not only enhances the lush landscape of the region but also signals the approaching autumn. As the warmth of summer gives way to cooler, wetter weather, Trieste’s vibrant scenery is refreshed, underlining a seasonal transition that brings both beauty and a necessary replenishment to the area's water resources.
Trieste experiences a notable shift in humidity levels as the summer gives way to autumn. While the warmer months of June and July boast the lowest humidity, at 69% and 63% respectively, September marks a slight uptick, returning to a more moderate 64%. This transition reflects a gradual increase that leads into the wetter fall months, particularly October, where humidity jumps to a more substantial 83%. As the year progresses, Trieste moves from the drier summer ambiance toward the higher humidity typical of late autumn, with November and December nearing 89% and 88%, respectively. This pattern showcases how Trieste’s climate balances between warmer, drier seasons and the moisture-laden atmosphere as the year draws to a close.
As September arrives in Trieste, Italy, the UV Index reaches a comfortable 7, placing it in the high exposure category, with a burn time of 25 minutes. This indicates a slight decrease from the scorching levels of summer, where the UV Index peaked at 9 in July and June, both categorized as very high. However, compared to earlier months like April and May, when the Index ranged from 6 to 8, September still holds considerable sun strength. This transitional month encourages outdoor activities, but it's essential to remain vigilant and protect your skin from prolonged exposure. For detailed information on UV levels throughout the year, visit Trieste UV Index.
UV Risk Categories
As September unfolds in Trieste, Italy, the city enjoys a delightful transition into autumn, boasting 326 hours of sunshine. This marks a gentle decline from the sun-drenched days of summer, where July peaks at an impressive 430 hours. The sunlight begins to wane, yet September still offers a generous amount, overshadowing the earlier months like January and February, which struggle with just 182 and 223 hours respectively. This pattern reveals a clear trend: as the year progresses, Trieste basks in increasing daylight until the summer climax, before gracefully easing into the cozy embrace of autumn. The city's rich history and stunning coastal views become even more enchanting during this golden month, inviting both locals and visitors to revel in the bright, soft days that September generously provides.
In September, Trieste, Italy, enjoys a notable chance of sunny weather with a 56% likelihood of sunshine, setting it apart as one of the more favorable months for clear skies. This optimism for sunshine follows a relatively sunny August (55%) and continues the trend seen throughout the summer months. While the sunny chances decline in the subsequent months, September perfectly balances the lingering warmth of summer and the crispness of early autumn, making it an ideal time to explore the city's alluring coastline and vibrant cultural scenes. As the season transitions, this sunny outlook provides both locals and visitors the perfect backdrop for enriching experiences before the cooler days of October arrive.
As summer fades into autumn, September in Trieste, Italy marks a gentle transition, with daylight lasting approximately 12 hours. This month embodies a diminishing yet vibrant sunlight, a drop from the sun-kissed heights of 15 hours seen in July and June. While daylight hours begin to retreat, nature still offers a stunning backdrop for outdoor activities, reminiscent of the longer, brighter days of summer that peaked in May and June. As the year progresses towards October, where daylight decreases to 10 hours, the patterns of light remind us of the ever-changing rhythms of the seasons, creating a captivating tapestry of time that invites both reflection and exploration.
As September unfolds in Trieste, Italy, the gentle caress of the breeze can be felt, with an average wind speed of 2.5 m/s (6 mph) providing a subtle backdrop to the city’s vibrant life. This month marks a shift from the warmer summer winds, which typically hover around 2.8 m/s in August, to the slightly brisker conditions that October promises with its 3.7 m/s (8 mph) average. While the wind doesn’t reach the more potent gusts of the upcoming fall months, it consistently reflects a pattern of overall fluctuation throughout the year. Notably, Trieste's windiest months are November and October, hinting at an invigorating transition as the seasons change. In September, the wind serves not only to cool but also to stir the essence of autumn, offering a serene yet dynamic atmosphere that beckons both locals and visitors to revel in the city's charm.
The weather in Trieste changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Trieste and find detailed weather information for every month.
September and January exhibit strikingly different weather patterns. In September, temperatures range from a mild 8°C (46°F) at night to a warm 30°C (87°F) during the day, with an average temperature of 19°C (66°F). This month also sees considerable rainfall, with 183 mm (7.2 in) of precipitation over 12 days, and humidity levels around 64%. In contrast, January experiences much colder temperatures, with lows plummeting to -8°C (17°F) and an average temperature of just 4°C (39°F). The maximum temperature only reaches 12°C (54°F), and the month is significantly drier, with precipitation measuring 66 mm (2.6 in) over 7 days, accompanied by higher humidity at 88%. For more detailed insights, you can check out Trieste weather in January.
September and February present contrasting weather patterns. In September, temperatures range from a minimum of 8°C to a maximum of 30°C, with an average of 19°C, making it a warm month. Rainfall is significant, totaling 183 mm over approximately 12 days, accompanied by a moderate humidity level of 64%. In contrast, February experiences much cooler temperatures, with a minimum of -7°C and a maximum of 19°C, averaging only 6°C. Despite lower precipitation at 128 mm over about 10 days, February's humidity is higher at 82%, contributing to a more damp and chilly atmosphere. For more details on February's weather in Trieste, you can check Trieste weather in February.
September and March present quite contrasting weather conditions. In September, temperatures range more widely from a chilly minimum of 8°C (46°F) to a warm maximum of 30°C (87°F), making it a month full of warm days as summer transitions into autumn. However, it also experiences significant rainfall, with precipitation reaching 183 mm (7.2 in) over approximately 12 days, accompanied by a humidity level of 64%.
In contrast, March features cooler temperatures, with a minimum of -10°C (14°F) and a maximum of 20°C (69°F), indicating a lingering chill as winter gives way to spring. Although March has lower total precipitation of 87 mm (3.4 in) over 10 days, it boasts slightly higher humidity at 73%. For more detailed information on March weather, you can refer to Trieste weather in March.
In comparing the weather of September and April, notable differences in temperature and precipitation emerge. September enjoys a wider temperature range, with averages around 19°C (66°F) and maximums reaching up to 30°C (87°F), while April’s temperatures are cooler, peaking at 24°C (75°F) and dipping to as low as -1°C (30°F). Additionally, September experiences more rainfall, totaling 183 mm (7.2 in) over 12 days, compared to April's 117 mm (4.6 in) over just 10 days. Interestingly, April has higher humidity at 73%, compared to September's 64%. For more specific insights into April weather, you can check this link: Trieste weather in April.
When comparing the weather in September and May, September typically enjoys warmer temperatures, with averages around 19°C (66°F) and highs reaching up to 30°C (87°F), compared to May's average of 16°C (61°F) and maximum of 26°C (79°F). However, both months experience similar levels of precipitation, with September receiving 183 mm (7.2 in) over about 12 days and May slightly less at 175 mm (6.9 in) but across more days—19 in total. Humidity levels are also higher in May at 70%, compared to 64% in September. For more specific details about the weather in May, you can check Trieste weather in May.
In comparing the weather of September and June, it's evident that both months offer distinctive experiences. September sees a minimum temperature of 8°C (46°F) and can reach a maximum of 30°C (87°F), with an average of 19°C (66°F), while June has slightly warmer temperatures ranging from a low of 11°C (52°F) to a high of 33°C (91°F), averaging at 21°C (71°F). Precipitation is more frequent in September, totaling 183 mm (7.2 in) over 12 days, compared to June's 105 mm (4.1 in) over 9 days. Humidity levels are also relatively high, with September at 64% and June slightly higher at 69%. For more specific insights about the weather in June, check out Trieste weather in June.
Comparing the weather in September and July reveals notable differences in temperature and precipitation patterns. In September, the temperatures range from a minimum of 8°C (46°F) to a maximum of 30°C (87°F), with an average of 19°C (66°F). This month also sees a higher amount of precipitation, totaling 183 mm (7.2 in) over about 12 days and a humidity level of 64%. In contrast, July tends to be warmer, with temperatures ranging from a minimum of 15°C (59°F) to a maximum of 32°C (91°F), and an average of 23°C (73°F). The precipitation in July is significantly lower at 93 mm (3.6 in), occurring over 13 days and accompanied by a slightly lower humidity of 63%. For more detailed information, you can visit Trieste weather in July.
September showcases a noticeable transition in weather compared to August. While August boasts warmer temperatures with a minimum of 13°C and an average of 23°C, September cools down to a minimum of 8°C and an average of 19°C. The maximum temperatures also drop, from 34°C in August to 30°C in September. Additionally, September experiences significantly more rainfall, with 183 mm falling over 12 days compared to August's 89 mm over 10 days. The humidity levels rise from 51% in August to 64% in September, adding to the perception of a more humid and cooler climate as summer gives way to autumn. For more details on August weather, you can refer to Trieste weather in August.
In September, the weather features a wider range of temperatures, with a minimum of 8°C (46°F) and a maximum reaching 30°C (87°F), resulting in an average of 19°C (66°F). The month is fairly wet, with 183 mm (7.2 in) of precipitation over 12 days and a humidity level of 64%. In contrast, October sees cooler temperatures, with minimums dropping to 6°C (43°F) and maximums peaking at 22°C (72°F), leading to an average temperature of 14°C (58°F). Precipitation decreases to 126 mm (5.0 in) over 10 days, but humidity rises notably to 83%. For those looking to understand what to expect during this transition into fall, check out Trieste weather in October.
September and November showcase a noticeable shift in weather conditions. In September, temperatures range from a minimum of 8°C (46°F) to a maximum of 30°C (87°F), with an average of 19°C (66°F), making it a warmer month overall. However, November sees a significant drop in temperatures, with a minimum of 0°C (33°F) and an average of 10°C (50°F), peaking at 18°C (65°F). Precipitation also increases slightly in November, totaling 199 mm (7.8 in) over 13 days compared to September's 183 mm (7.2 in) over 12 days. Additionally, humidity levels rise markedly in November, reaching 89%, compared to 64% in September. For more specific insights into November weather, you can visit Trieste weather in November.
In September, the weather is generally milder with temperatures ranging from a minimum of 8°C (46°F) to a maximum of 30°C (87°F), featuring an average of 19°C (66°F). The month experiences moderate precipitation totaling 183 mm (7.2 in) over approximately 12 days, accompanied by a humidity level of 64%. In contrast, December ushers in much colder conditions, with temperatures dipping to a minimum of -2°C (29°F) and averaging around 6°C (42°F), peaking at 14°C (58°F). Although precipitation slightly decreases to 166 mm (6.5 in) over the same number of days, the humidity rises significantly to 88%. For more detailed information on December weather, visit Trieste weather in December.
As September unfolds in Trieste, the weather shifts into a delightful autumnal rhythm, providing a refreshing contrast to the sweltering summer months. With average temperatures settling around a mild 19°C (66°F), this month offers a pleasant reprieve from the heat, making it ideal for exploring the city’s stunning coastal views. September also sees an increase in precipitation, bringing rejuvenating rain, while humidity levels remain comfortable. This unique blend of climate characteristics creates an inviting atmosphere for both locals and visitors alike. To learn more about what to expect throughout the year, check out Trieste Climate.