August Weather in Siena, Italy

Last updated: March 24, 2025

Siena, Italy, in August offers a vibrant tapestry of weather experiences. With maximum temperatures soaring to 37°C (99°F) and an average of 25°C (77°F), visitors can bask in the warmth of summer days. The evenings cool down to a comfortable minimum of 12°C (53°F), perfect for leisurely strolls through the historic streets. While the month sees around 34 mm (1.3 in) of precipitation spread across 5 days, humidity levels remain moderate at 55%, making it an inviting time to explore the rich culture and breathtaking landscapes Siena has to offer.

August Temperature in Siena

In August, Siena basks in the warmth of summer, showcasing temperatures that are both inviting and vibrant. With night temperatures hovering around a comfortable 12°C (53°F) and daytime highs reaching up to a sizzling 37°C (99°F), this month offers an ideal blend of warmth for sun-seekers. The average temperature of 25°C (77°F) creates a perfect backdrop for exploring the city’s rich history, indulging in local cuisine, or sipping wine in its picturesque squares. As the hottest month, August stands out with a significant leap from the prior months, reflecting a steady upward trend in temperatures throughout the summer. Whether you're strolling through medieval streets or relaxing in a café, Siena in August is a delightful experience bathed in sunshine.

August Weather in Siena: Daily Temperature Highs, Lows, and Averages

The chart illustrates August temperature patterns in Siena, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec414548546271757768595144
Data source: Temperature data for Siena 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.

August Precipitation in Siena

In August, Siena experiences a notable dip in precipitation, recording just 34 mm (1.3 in) across 5 days. This is the driest month of the year, following a pattern of decreasing rainfall from the wetter spring months, which peak in April and May. The summer months of July and August typically bring less rain, indicative of typical Mediterranean climates. As the warm season concludes, August sets the stage for the wetter September, where precipitation rises significantly again to 84 mm (3.3 in) over 9 days. This transition highlights a dynamic weather pattern in Siena, showcasing how summer dryness gives way to the refreshing rains of autumn.

August Precipitation Trends in Siena

The chart displays monthly precipitation patterns in Siena, with values for each month alongside August's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how August's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec4468618191383834849114898
Data source: Precipitation data for August generated using information from the Copernicus Climate Change Service.
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August Humidity in Siena

In August, Siena, Italy, experiences a refreshing low humidity level of 55%, marking the driest month of the year. This decline continues from July’s 57%, highlighting a distinct trend toward drier conditions as summer peaks. The decreasing humidity not only enhances outdoor enjoyment but also contributes to the warm, sun-soaked days typical of this time. As the season transitions into autumn, humidity begins to rise again in September, reaching 66%, but August remains a standout for those seeking a more comfortable climate amidst the bustling Italian summer.

August Average Humidity in Siena

This chart illustrates the average monthly humidity levels in Siena, with August's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how August's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec84%76%68%70%69%62%57%55%66%79%84%83%
Data source: Humidity data for August generated using information from the Copernicus Climate Change Service.

August UV Index in Siena

In August, Siena, Italy, experiences a very high UV Index of 9, indicating a significant potential for skin damage with prolonged exposure to the sun. This month follows a trend of increasing UV intensity that begins in the spring, peaking during the summer months. As the burn time shortens to just 15 minutes, it’s essential to take protective measures while enjoying the warm Italian sun. With September bringing a slight dip to a UV Index of 7, the need for vigilance remains high as the summer wanes. So, whether you’re exploring the historic streets or lounging outdoors, remember to safeguard your skin. For more detailed information, check out the Siena UV Index.

Maximum UV Index Levels in Siena for August

The chart shows the monthly maximum UV Index (UVI) for Siena in August, 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.
JanFebMarAprMayJunJulAugSepOctNovDec24578101097532
Data source: Siena August 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.

August Sunshine in Siena

August in Siena, Italy, continues the summer's warm embrace with 402 hours of sunshine, providing a perfect backdrop for exploring the city's rich history and vibrant culture. Following the peak sunshine of July, which boasts an impressive 432 hours, August experiences a gentle decline yet remains one of the sunniest months of the year. As the joyful buzz of summer begins to gracefully transition into early autumn, visitors can still bask in the golden glow of late summer while enjoying the stunning landscapes and historic architecture. This trend of abundant sunshine in the warmer months is a delightful invitation to experience Siena at its brightest.

Monthly Sunshine Duration in Siena: August Highlighted

The August sunshine duration represents the total number of hours Siena experiences direct sunlight during the month of August, excluding cloudy or obstructed periods. This chart compares the sunshine duration of August with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec185h231h311h340h383h417h432h402h335h304h228h216h
Data source: Siena August Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Siena During August

In August, Siena basks in the embrace of a sunny disposition, boasting a 66% chance of sunshine. This marks a significant increase compared to the earlier months of the year, reflecting a broader trend of rising sunny days as summer progresses. Starting with a modest 31% in January, the likelihood of clear skies steadily climbs, peaking in July at 64% before reaching its height in August. As summer transitions into early autumn, the chance of sunshine remains favorable at 55% in September, promising lingering warmth and vibrancy for those exploring this enchanting Italian city. With this тенденция, visitors can expect ideal conditions for enjoying Siena’s stunning landscapes and rich history.

Percentage of Sunny Days in August in Siena

The chart illustrates the percentage of sunny days in Siena throughout the year, with August 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 Siena experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec31%42%62%45%43%58%64%66%55%43%32%37%
Data source: Siena August chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Siena in August

In August, Siena, Italy experiences a delightful transition in daylight duration, enjoying approximately 13 hours of sunlight each day. This month marks a gentle decline from the peak of 15 hours in June, signaling the slow shift towards autumn. As summer draws to a close, day lengths remain generous, providing ample time for outdoor adventures and cultural exploration. Following August, daylight hours gradually decrease, with September bringing 12 hours of daylight, reinforcing the rhythmic ebb and flow of the seasons. This trend highlights Siena's vibrant summer atmosphere, perfectly balanced with a soft reminder of the approaching fall.

Average Daylight Hours in Siena for August

The chart illustrates the variation in daylight duration in Siena throughout the year, with August highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec9h 23m10h 31m11h 57m13h 25m14h 40m15h 18m14h 58m13h 51m12h 27m10h 59m9h 41m9h 2m
Data source: Siena daylight hours, calculated by summing the hours between sunrise and sunset for each day.

August Winds in Siena

In Siena, Italy, the August wind carries a gentle whisper, with an average speed of 2.1 m/s (5 mph), providing a mild respite from the summer heat. This month typically features the second-lowest wind speed of the year, reflecting a trend of more tranquil breezes compared to the spring months, which see higher averages, like 2.6 m/s in April and May. Interestingly, as the seasons transition into autumn, winds pick up slightly, returning to 2.7 m/s in October. This gradual ebb and flow creates a soothing atmosphere throughout the summer, making Siena a delightful destination to savor the warm days and balmy nights, amplified by the light caresses of the August breeze.

Average August Wind Speed in Siena

The chart displays monthly wind speed patterns in Siena, with values for each month shown alongside August's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how August's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.72.42.42.62.61.82.32.1 m/s2.02.72.52.2
Data source: Siena August wind data, generated using information from the Copernicus Climate Change Service.

How August Weather in Siena Compares to Other Months

The weather in Siena changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of August's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Siena and find detailed weather information for every month.

August and January present a stark contrast in weather conditions. In August, the temperatures can rise significantly, with daily averages reaching around 25°C (77°F) and maximums soaring to 37°C (99°F). The month sees relatively low precipitation at 34 mm (1.3 in) over about 5 days, accompanied by mild humidity levels of 55%. In contrast, January experiences much colder temperatures, with averages around 5°C (41°F) and lows plummeting to -5°C (23°F). Precipitation is slightly higher at 44 mm (1.7 in) over approximately 7 days, coupled with a much higher humidity of 84%. This comparison highlights the seasonal shift from the warmth of summer to the chill of winter. For more detailed information on January weather, you can refer to Siena weather in January.

August and February present stark contrasts in weather. August typically enjoys warmer temperatures, ranging from a minimum of 12°C (53°F) to a scorching maximum of 37°C (99°F), with an average of 25°C (77°F). It experiences relatively low precipitation at 34 mm (1.3 in) over about 5 days, coupled with a moderate humidity level of 55%. In contrast, February offers much cooler conditions, with temperatures ranging from a chilly minimum of -5°C (23°F) to a maximum of 20°C (68°F), averaging just 7°C (46°F). Precipitation is higher during this month at 68 mm (2.7 in) across approximately 8 days, and humidity is also elevated at 76%. For more detailed insights into February weather, you can check Siena weather in February.

When comparing the weather of August and March, significant differences stand out. August boasts warmer temperatures, with averages reaching a comfortable 25°C (77°F) and highs soaring up to 37°C (99°F). In contrast, March experiences much cooler weather, where average temperatures hover around 9°C (49°F), with nighttime lows plummeting to -11°C (12°F). Additionally, August sees lower precipitation levels at 34 mm (1.3 in) over about 5 days, while March is wetter, receiving 61 mm (2.4 in) of rain across roughly 8 days. The humidity in March is also higher at 68%, compared to August's 55%. For more detailed insights on March weather, check out this link: Siena weather in March.

When comparing the weather in August and April, notable differences emerge. August typically enjoys warmer temperatures, with a minimum of 12°C (53°F), an average of 25°C (77°F), and a maximum reaching as high as 37°C (99°F). In contrast, April experiences much cooler temperatures, with a minimum of -3°C (27°F), an average of 12°C (55°F), and a maximum of 26°C (79°F). Additionally, April sees more rainfall, averaging 81 mm (3.2 in) over about 10 days, while August has significantly less precipitation at 34 mm (1.3 in) over just 5 days. Humidity levels are also higher in April at 70%, compared to 55% in August. For more details about April weather specifically, you can check Siena weather in April.

When comparing the weather in August to that in May, a clear contrast emerges. August typically boasts warmer temperatures, with averages around 25°C (77°F), peaking at a maximum of 37°C (99°F). In contrast, May experiences cooler temperatures, averaging 16°C (62°F) and reaching a maximum of 31°C (89°F). Precipitation also varies significantly; May is notably wetter with 91 mm (3.6 in) across 13 days, while August sees less rain, totaling just 34 mm (1.3 in) over 5 days. Additionally, humidity levels are higher in May at 69%, compared to 55% in August. For a deeper look into May weather specifics, check out Siena weather in May.

In comparing the weather of August and June, August typically enjoys warmer temperatures, with an average of 25°C (77°F) compared to June's 22°C (71°F). The maximum temperature in August can reach up to 37°C (99°F), making it the hotter month overall, while June tops out at 36°C (96°F). Both months experience a relatively low amount of rainfall, but June has slightly higher precipitation levels at 38 mm (1.5 in) over 6 days compared to August's 34 mm (1.3 in) over 5 days. Additionally, humidity is generally a bit higher in June at 62%, compared to 55% in August. For more detailed information, you can check Siena weather in June.

In comparing the weather of August and July, we see that both months feature warm temperatures, but August tends to be slightly hotter on average. August has a minimum temperature of 12°C (53°F), an average of 25°C (77°F), and a maximum of 37°C (99°F), while July offers a minimum of 13°C (56°F), an average of 24°C (76°F), and a maximum of 36°C (97°F). Precipitation is slightly lower in August, with 34 mm (1.3 in) over 5 days, compared to July's 38 mm (1.5 in) over 6 days. Humidity levels are also slightly lower in August, at 55%, compared to 57% in July. For more detailed information, you can check Siena weather in July.

August generally presents warmer weather compared to September, with temperatures ranging from a minimum of 12°C (53°F) to a maximum of 37°C (99°F) and an average of 25°C (77°F). In contrast, September's cooler climate features a minimum temperature of 7°C (45°F) and a maximum of 32°C (90°F), averaging around 20°C (69°F). While August experiences relatively low precipitation at 34 mm (1.3 in) over five days, September sees a significant increase in rainfall, totaling 84 mm (3.3 in) over nine days, also resulting in higher humidity levels at 66%. For more detailed insights on the weather during this month, you can visit Siena weather in September.

August and October present stark contrasts in weather. In August, temperatures range from a minimum of 12°C (53°F) to a scorching maximum of 37°C (99°F), with an average of 25°C (77°F). The month sees relatively low precipitation at 34 mm (1.3 in) over about 5 days, accompanied by a comfortable humidity level of 55%.

In contrast, October experiences cooler temperatures, with a minimum of 5°C (40°F) and a maximum of 27°C (81°F), averaging just 15°C (59°F). This month also brings increased moisture, with precipitation reaching 91 mm (3.6 in) over 8 days and significantly higher humidity at 79%. For those interested in specific conditions, you can learn more about the October climate in Tuscany by visiting Siena weather in October.

August and November present a stark contrast in weather conditions. In August, temperatures range from a mild 12°C (53°F) at night to a scorching 37°C (99°F) during the day, with an average of 25°C (77°F). The humidity sits at a moderate 55%, and rainfall is relatively light, with just 34 mm (1.3 in) over about 5 days. In sharp contrast, November experiences much cooler temperatures, with lows plummeting to -3°C (27°F) and an average of 11°C (51°F). Daytime highs reach a modest 19°C (66°F) and the month is considerably wetter, receiving 148 mm (5.8 in) of precipitation over 15 days, coupled with a high humidity level of 84%. For more specific details, you can check Siena weather in November.

In August, the weather is warm and often sweltering, with daily temperatures ranging from a minimum of 12°C (53°F) to a maximum of 37°C (99°F), averaging around 25°C (77°F). The humidity is moderate at 55%, and the month sees relatively low precipitation, with only 34 mm (1.3 in) falling over an average of five days. In stark contrast, December brings much colder temperatures, ranging from a frigid -4°C (25°F) to a milder 16°C (61°F), with an average of just 7°C (44°F). The month is significantly wetter, with total precipitation reaching 98 mm (3.8 in) spread over 11 days, and humidity levels higher at 83%. For more details, visit Siena weather in December.

Compare Siena's Climate with Cities Worldwide

Conclusion: What to Expect From August Weather in Siena

August in Siena brings a sizzling blend of summer warmth and occasional refreshing breezes, making it a vibrant time to explore the city. With temperatures soaring to a maximum of 37°C (99°F) and a comfortable average of 25°C (77°F), it's notably warmer than the preceding months. While August does see a slight increase in humidity at 55%, the rain remains scarce with only 34 mm of precipitation over just five days. This unique combination of heat and low rainfall creates the perfect backdrop for enjoying Siena's stunning landscapes and rich culture. For more insights into what to expect throughout the year, check out the detailed information at Siena Climate.