September Weather in Trevi, Italy

Last updated: March 24, 2025

September in Trevi, Italy, offers a delightful balance of warmth and freshness, with maximum temperatures reaching up to 31°C (88°F) and an average of 18°C (65°F). Visitors can expect a refreshing dip in the evenings, with minimum temperatures dropping to 5°C (42°F). Although the month experiences 76 mm (3.0 in) of precipitation over 8 days, this moisture helps maintain the region's lush green landscapes. With a moderate humidity level of 67%, September is an enchanting time to explore Trevi's picturesque charm and serene ambiance.

September Temperature in Trevi

In September, Trevi experiences a delightful transition into early autumn, with temperatures showcasing a gentle decline from the summer highs. The average temperature sits comfortably at 18°C (65°F), while daytime highs can reach a pleasant 31°C (88°F), allowing for ideal conditions to explore the charming streets and breathtaking landscapes. As the month progresses, the nights begin to cool down, with lows around 5°C (42°F). This shift marks a perfect time to enjoy the lingering warmth of summer while also savoring the crisp, refreshing air of fall, creating an inviting atmosphere for both locals and visitors alike.

September Weather in Trevi: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Trevi, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec384345515969747565574941
Data source: Temperature data for Trevi generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Trevi

In September, Trevi experiences a notable shift in its weather patterns, with precipitation levels rising to 76 mm (3.0 in) across 8 days of rain. This marks a significant increase compared to the drier summer months, where July recorded merely 32 mm (1.3 in), and June brought only 39 mm (1.5 in). As the landscape transitions into autumn, the increase in rainfall not only replenishes the earth but also sets the stage for vibrant fall foliage, inviting both locals and visitors to appreciate the changing scenery. This upward trend in precipitation continues as Trevi heads into October and November, with the latter month typically reaching 104 mm (4.1 in), signaling the onset of the wet season.

September Precipitation Trends in Trevi

The chart displays monthly precipitation patterns in Trevi, with values for each month alongside September's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec55678166893932417654104115
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Trevi

As summer transitions to autumn in Trevi, Italy, September brings a notable increase in humidity, reaching 67%. This marks a shift from the notably dry months of July and August, where humidity levels dipped to their lowest at 59% and 54%, respectively. While still lower than the winter months, which see humidity soar to 86% in December, September's humidity reflects a gradual return towards the generally wetter conditions characteristic of autumn. This pattern highlights the delicate balance of Trevi's climate, as it shifts from the warm and arid summer days to the crisp, refreshing embrace of the approaching fall.

September Average Humidity in Trevi

This chart illustrates the average monthly humidity levels in Trevi, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec85%78%69%71%71%63%59%54%67%79%84%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Trevi

As summer wanes, September in Trevi, Italy, greets visitors with a UV Index of 7, maintaining a high exposure category that calls for caution. This drop from the peak summer months, when the index reached heights of 9 and 10, signals a subtle shift in sun safety protocols. With a burn time of approximately 25 minutes, it’s essential to ensure adequate sun protection during outdoor activities. While the UV levels are lower than in the height of summer, visitors should still be mindful of the sun’s rays. For more detailed insights on sun exposure trends, check out the Trevi UV Index.

Maximum UV Index Levels in Trevi for September

The chart shows the monthly maximum UV Index (UVI) for Trevi in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec24679101097532
Data source: Trevi September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Trevi

As summer begins to ebb, September in Trevi, Italy, still bathes in a warm embrace of sunlight with an impressive 333 hours of sun. Although the days grow shorter, this delightful month sees a marked transition from the peak summer brightness of July, which boasts the highest at 430 hours, to the more mellow yet still inviting glow of autumn. The lingering warmth is reminiscent of August's 399 hours, allowing visitors to enjoy the stunning landscapes and charming streets in pleasant weather. As the year progresses, sunlight gradually declines, but September holds onto that summer spirit just a little longer, making it a perfect time to explore Trevi's beauty before the cooler months set in.

Monthly Sunshine Duration in Trevi: September Highlighted

The September sunshine duration represents the total number of hours Trevi experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec178h233h311h348h390h417h430h399h333h302h224h218h
Data source: Trevi September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Trevi During September

September in Trevi, Italy, offers a welcoming blend of warm days and relatively sunny weather, boasting a 56% chance of sunshine. This figure reflects a slight dip from the peak summer months of July and August, where sunshine chances soar to 63% and 69% respectively. However, September still outshines earlier months such as April and May, which sit at just 45%. As autumn approaches, the transitional weather provides a beautiful backdrop for exploring Trevi's charming landscapes, making it a delightful time for visitors seeking a mix of pleasant sun and cooler breezes.

Percentage of Sunny Days in September in Trevi

The chart illustrates the percentage of sunny days in Trevi throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Trevi experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec30%52%62%45%45%61%63%69%56%38%25%41%
Data source: Trevi September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Trevi in September

As summer gives way to autumn in Trevi, Italy, September marks a gentle transition in daylight duration, with the sun gracing the sky for 12 hours each day. This signals a decline from the long, sun-soaked days of June and July, which enjoyed a peak of 15 hours. The month of September captures the essence of early fall, providing a harmonious blend of warmth and crispness as daylight gradually diminishes. Following September, October further reduces daylight to 10 hours, paving the way for the shorter days of winter. This gradual change not only paints the landscape in stunning fall hues but also invites locals and visitors alike to savor the lingering warmth before the chill of winter sets in.

Average Daylight Hours in Trevi for September

The chart illustrates the variation in daylight duration in Trevi throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 24m10h 31m11h 57m13h 24m14h 39m15h 16m14h 56m13h 50m12h 26m10h 59m9h 43m9h 3m
Data source: Trevi daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Trevi

As summer transitions to autumn in Trevi, Italy, the September winds offer a gentle respite, with an average speed of 1.9 m/s (4 mph), marking the year’s lowest. This subtle breeze contrasts with the more spirited gusts of May and March, where wind speeds reach 2.8 m/s (6 mph) and 2.5 m/s (6 mph), respectively. Throughout the warmer months, the winds typically hover around 2.4 to 2.8 m/s (5 to 6 mph), creating a lively atmosphere. However, as September arrives, the calmness of the air hints at the cozy embrace of fall, providing a perfect setting for leisurely strolls through the picturesque streets of Trevi, where the charm of the landscape softens under fading summer light.

Average September Wind Speed in Trevi

The chart displays monthly wind speed patterns in Trevi, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.52.32.52.42.82.02.42.31.9 m/s2.52.32.4
Data source: Trevi September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Trevi Compares to Other Months

The weather in Trevi 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 Trevi and find detailed weather information for every month.

In comparison to September, January presents a stark contrast in weather conditions. While September boasts a pleasant average temperature of 18°C (65°F) with highs reaching 31°C (88°F), January's average temperature drops significantly to just 3°C (39°F), with maximums only reaching 15°C (59°F). Precipitation levels are relatively higher in September at 76 mm (3.0 in), but January still sees considerable rainfall, amounting to 54 mm (2.1 in) over 9 days. Additionally, January's humidity is notably higher at 85%, compared to September's 67%, leading to a chillier and potentially damp atmosphere. For those wanting to explore the specifics of Trevi's winter climate, Trevi weather in January offers detailed insights.

In September, the weather is typically warm, with average temperatures ranging from a cool 5°C (42°F) to a pleasant high of 31°C (88°F), accompanied by a moderate level of humidity at 67%. Despite the warmth, September does see some rainfall, with around 76 mm (3.0 in) over approximately 8 days. In contrast, February experiences significantly colder temperatures, with highs only reaching 18°C (65°F) and lows plummeting to -14°C (7°F), resulting in an average temperature of just 6°C (43°F). The month sees a bit less rainfall, totaling 67 mm (2.6 in) over 9 days, while humidity rises slightly to 78%. For more detailed information on February weather in Trevi, check out Trevi weather in February.

In September, temperatures range from a mild 5°C (42°F) to a warm 31°C (88°F), with an average of 18°C (65°F), creating a pleasant late summer atmosphere. The month sees about 76 mm (3.0 in) of precipitation over roughly 8 days, and the humidity hovers around 67%. In contrast, March brings much cooler temperatures, starting at a minimum of -18°C (0°F) and peaking at 20°C (68°F), with an average temperature of 7°C (45°F). March experiences slightly more precipitation at 80 mm (3.2 in) over about 9 days, accompanied by a humidity level of 69%. For a detailed look at the weather specifics in March, visit Trevi weather in March.

September and April present contrasting weather conditions. In September, temperatures range from a cool 5°C (42°F) at night to a warm maximum of 31°C (88°F) during the day, averaging around 18°C (65°F). The humidity stays relatively high at 67%, and the month sees about 76 mm (3.0 in) of precipitation over approximately 8 days. In contrast, April starts off much chillier, with nighttime lows dipping to -4°C (25°F) and daytime highs reaching 24°C (75°F), leading to an average temperature of 11°C (52°F). Although April has slightly less rainfall at 66 mm (2.6 in) over about 10 days, the humidity is marginally higher at 71%. For more details about the weather, you can refer to Trevi weather in April.

When comparing the weather in September and May, notable differences emerge in both temperature and precipitation patterns. September tends to be warmer, with average temperatures ranging from a minimum of 5°C (42°F) to a maximum of 31°C (88°F), whereas May sees lower temperatures, averaging between 1°C (35°F) and 29°C (84°F). In terms of precipitation, May is slightly wetter with 89 mm (3.5 in) over 14 days compared to September's 76 mm (3.0 in) over just 8 days, resulting in higher humidity levels in May at 71% versus September's 67%. For more detailed insights, you can check out Trevi weather in May.

In comparing the weather of September and June, September tends to be slightly cooler overall, with average temperatures ranging from a minimum of 5°C (42°F) to a maximum of 31°C (88°F), while June experiences a minimum of 6°C (44°F) and can reach up to 34°C (93°F). June is generally drier, with only 39 mm (1.5 in) of precipitation over 6 days compared to September's 76 mm (3.0 in) over 8 days. Additionally, humidity levels are somewhat higher in September at 67%, compared to June's 63%. For more information on June weather specifics, you can visit Trevi weather in June.

When comparing the weather in September and July, notable differences emerge. September experiences a broader temperature range, with minimums dipping to 5°C (42°F) and maximums reaching up to 31°C (88°F), making it milder overall with an average temperature of 18°C (65°F). In contrast, July is significantly warmer, featuring a higher average of 23°C (74°F) and maximum temperatures peaking at 35°C (96°F). Additionally, precipitation in September is more pronounced, with 76 mm (3.0 in) spread over approximately 8 days, while July has just 32 mm (1.3 in) of rain over 5 days. Humidity levels are also higher in September at 67%, compared to July's 59%. For more details on July's weather, you can refer to Trevi weather in July.

In September, temperatures in Trevi generally show a notable decrease compared to August, with a minimum of 5°C (42°F) and an average of 18°C (65°F), dropping from the warmer average of 24°C (75°F) in August. The maximum temperatures in September peak at 31°C (88°F), which are significantly lower than the sweltering highs of 37°C (99°F) experienced in August. Additionally, September sees increased precipitation, averaging 76 mm (3.0 in) over 8 days, while August had only 41 mm (1.6 in) yet also with the same number of rainy days. Humidity levels rise in September to 67%, compared to 54% in August, contributing to a distinct shift in the overall weather experience from late summer to early autumn. For more detailed insights, you can refer to Trevi weather in August.

September exhibits a warmer climate with temperatures ranging from a minimum of 5°C (42°F) to a maximum of 31°C (88°F), averaging 18°C (65°F). This month also experiences more significant rainfall, amounting to 76 mm (3.0 in) over about 8 rainy days and a humidity level of 67%. In contrast, October sees a noticeable drop in temperature, with a minimum of 4°C (39°F), an average of 14°C (57°F), and a maximum of 25°C (78°F). Precipitation is lighter at 54 mm (2.1 in) over 7 days, while humidity slightly increases to 78%. For more detailed information about the weather during October, you can check Trevi weather in October.

September and November present a striking contrast in weather conditions. In September, temperatures range from a mild 5°C (42°F) at night to a warm 31°C (88°F) during the day, with an average of 18°C (65°F). The month receives about 76 mm (3.0 in) of precipitation over approximately 8 days and maintains a humidity level of 67%. In contrast, November experiences much colder temperatures, with a minimum of -3°C (27°F) and a maximum of 18°C (65°F), averaging only 10°C (49°F). This month is wetter, receiving 104 mm (4.1 in) of rain across 13 days, and the humidity increases to 84%. For more detailed insights into November weather, you can visit Trevi weather in November.

The weather in September is characterized by warmer temperatures, with averages around 18°C (65°F) and maximums reaching 31°C (88°F), making it a much more pleasant month for outdoor activities. In contrast, December brings a significant drop in temperature, with average highs of only 15°C (59°F) and chilly minimums that can plummet to -6°C (22°F). September also sees less precipitation, with 76 mm (3.0 in) over about 8 days, while December experiences higher rainfall totaling 115 mm (4.5 in) over 11 days, coupled with increased humidity at 86%. For more detailed insights about December’s conditions, you can check Trevi weather in December.

Compare Trevi's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Trevi

September in Trevi ushers in a delightful transition from the heat of summer, with average temperatures that offer a pleasant blend of warmth and coolness. While daytime highs can still reach a toasty 31°C, the evenings bring refreshing breezes, making it perfect for outdoor activities. This month also experiences a moderate level of precipitation, with a few days of light rain, which helps to nourish the landscape and cool the air. As humidity lingers around 67%, the overall climate feels comfortable, striking a balance that sets September apart from the more extreme temperatures of both summer and winter. To learn more about what to expect from the weather year-round, visit Trevi Climate.