May Weather in Siena, Italy

Last updated: March 24, 2025

In May, Siena, Italy, experiences a delightful blend of mild temperatures and occasional rainfall. With a maximum temperature reaching 31°C (89°F), residents and visitors can enjoy warm days, while the average settles at a comfortable 16°C (62°F). Nights can be cooler, dipping to a minimum of 3°C (37°F). Precipitation is quite frequent this month, with about 91 mm (3.6 in) of rain spread over 13 days, contributing to a humidity level of 69%. This vibrant mix of weather offers a unique atmosphere, perfect for exploring Siena's historic charm amidst spring blooms.

May Temperature in Siena

In Siena, Italy, the month of May marks a delightful transition into warmer weather, showcasing a vibrant increase in temperatures. With minimums rising to a refreshing 3°C (37°F) and average highs reaching a comfortable 31°C (89°F), this month is truly a springtime delight. The progression from the cooler temperatures of early spring in April, with its max at 26°C (79°F), indicates a clear upward trend towards the summer heat typical in June. May offers a perfect balance, ideal for strolling through Siena's enchanting streets or enjoying its stunning outdoor cafes, all while the lush Tuscan landscape blossoms into full vibrancy.

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

The chart illustrates May 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.

May Precipitation in Siena

In May, Siena experiences a noticeable shift in precipitation patterns, with an increase to 91 mm (3.6 in) over 13 days of rainfall, marking it as one of the wetter months of the year. This uptick continues the trend established in the preceding months, showcasing a steady rise from 44 mm in January to 81 mm in April. May's showers not only contribute to the city’s lush landscapes but also set the stage for the drier summer months ahead. The rainfall during this time highlights a vibrant transition into warmer weather, making it a unique month as residents and visitors alike enjoy both blooming gardens and refreshing downpours.

May Precipitation Trends in Siena

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

In May, Siena experiences a comfortable humidity level of 69%, maintaining a balance between the spring's lingering moisture and the drier summer months ahead. This reduction from April's 70% indicates a gradual trend towards lower humidity, following the pattern established from the previous months—January and February boast higher humidity at 84% and 76% respectively, tapering off to June's drier 62%. As the year progresses, the landscape shifts, with the summer bringing more comfortable conditions, exemplified by the consistently lower humidity percentages from July through August. Overall, May serves as a transitional period, where the air feels fresher, hinting at the sunnier and drier days that lie ahead.

May Average Humidity in Siena

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

May UV Index in Siena

As spring blossoms into summer, May in Siena, Italy heralds a significant leap in UV intensity, with a striking UV Index of 8, categorized as very high. This represents an important shift from the moderate levels of earlier months, where burn times shrink dramatically to just 15 minutes under the intensity of the sun. It's crucial for sun lovers and outdoor enthusiasts to embrace proper sun protection during this month, as the potential for skin damage increases substantially. This trend continues into June and July, where UV levels peak at 10, further emphasizing the need for vigilance. To stay informed and safe, check the detailed insights at Siena UV Index.

Maximum UV Index Levels in Siena for May

The chart shows the monthly maximum UV Index (UVI) for Siena in May, 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 May 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.

May Sunshine in Siena

In Siena, Italy, May ushers in a delightful surge of sunshine, with 383 hours of glorious daylight illuminating the Tuscan landscape. This notable increase is part of a broader trend, as the month stands as a vibrant transition between the cooler spring months and the sun-drenched summer. Following a gradual rise from 185 hours in January, the sunlight peaks in July with 432 hours, creating an inviting atmosphere that beckons both locals and visitors. As spring blossoms into summer, May's sun-kissed charm plays a crucial role in the emergence of Siena's picturesque beauty, making it an ideal time to explore its historic streets and enjoy the captivating outdoor cafes.

Monthly Sunshine Duration in Siena: May Highlighted

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

Chance of Sun in Siena During May

In May, Siena experiences a solid 43% chance of sunny weather, which highlights a slight dip from the previous month, April, at 45%. This trend suggests that while late spring offers a pleasant escape from the chill of winter, it doesn't guarantee abundant sunshine. As the year progresses into the summer months, the likelihood of sun steadily increases, skyrocketing to 64% in July and 66% in August. This indicates that if you're seeking sunnier skies, planning your visit for the height of summer might be your best bet. However, May still offers a charming blend of mild weather and occasional sunshine, perfect for enjoying Siena's stunning landscapes and historic architecture.

Percentage of Sunny Days in May in Siena

The chart illustrates the percentage of sunny days in Siena throughout the year, with May 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 May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Siena in May

As spring ascends into summer in Siena, Italy, the length of daylight reveals a remarkable transformation. Starting at a modest 9 hours in January, the days gradually lengthen, reaching 14 hours by May, marking the peak of spring's vibrancy. This surge continues into June with an impressive 15 hours, inviting outdoor adventures and sunlit strolls through the historic streets. As the season shifts again, July also enjoys 14 hours of daylight, but a gradual tapering begins, with August and September presenting 13 and 12 hours, respectively. By the time the leaves change, daylight dwindles back down to 10 hours in October, before settling at 9 hours once more through the winter months. This rhythmic ebb and flow not only reflects the changing seasons but also sets the stage for Siena's enchanting cultural celebrations throughout the year.

Average Daylight Hours in Siena for May

The chart illustrates the variation in daylight duration in Siena throughout the year, with May 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.

May Winds in Siena

As May arrives in Siena, Italy, the gentle breeze carries with it the promise of warmer days ahead. With an average wind speed of 2.6 m/s (6 mph), the wind in May mirrors the conditions of the previous month, providing a refreshing backdrop to the blooming landscapes. This mild windiness is a pleasant transition from the slightly stronger breezes of April, while preceding the lighter winds that characterize the summer months of June and July. Overall, May offers a harmonious blend of comfort and a hint of freshness, making it an ideal time to explore the charming streets and scenic vistas of this historic city.

Average May Wind Speed in Siena

The chart displays monthly wind speed patterns in Siena, with values for each month shown alongside May's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how May's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.72.42.42.62.6 m/s1.82.32.12.02.72.52.2
Data source: Siena May wind data, generated using information from the Copernicus Climate Change Service.

How May 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 May'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.

May and January present contrasting weather conditions. In May, temperatures range from a minimum of 3°C (37°F) to a maximum of 31°C (89°F), with an average of 16°C (62°F), making it considerably warmer than January, which has temperatures between -5°C (23°F) and 15°C (59°F), averaging only 5°C (41°F). May also tends to be wetter, receiving 91 mm (3.6 in) of precipitation over about 13 days, compared to January's 44 mm (1.7 in) over just 7 days. Additionally, May has a lower humidity level of 69%, while January's humidity is notably higher at 84%. For more detailed insights on January weather, you can check Siena weather in January.

May and February present contrasting weather patterns, highlighting the transition from winter to late spring. In May, temperatures rise significantly, with a minimum of 3°C (37°F) and a pleasant average of 16°C (62°F), peaking at a warm 31°C (89°F). Conversely, February remains much colder, with minimum temperatures dipping to -5°C (23°F) and an average of only 7°C (46°F), peaking at 20°C (68°F). Precipitation in May is slightly higher at 91 mm (3.6 in) over 13 days, compared to February’s 68 mm (2.7 in) spanning 8 days. Additionally, while May's humidity sits at 69%, February's is notably higher at 76%, contributing to a chillier feel during the winter month. For more detailed information on February weather in Siena, you can visit Siena weather in February.

In comparing the weather between May and March, May typically experiences significantly warmer temperatures, with a minimum of 3°C (37°F) and an average high of 31°C (89°F), while March sees much cooler conditions, ranging from a minimum of -11°C (12°F) to a maximum of 23°C (73°F). Additionally, May is wetter, receiving 91 mm (3.6 in) of precipitation over 13 days compared to March's 61 mm (2.4 in) over 8 days. Despite this increase in rainfall, humidity levels remain similar, with May at 69% and March slightly lower at 68%. For a closer look at March weather specifics, you can visit Siena weather in March.

In comparing the weather of May and April, May exhibits a wider temperature range, with a minimum of 3°C (37°F), an average of 16°C (62°F), and a maximum reaching 31°C (89°F). In contrast, April starts off cooler, with temperatures dipping as low as -3°C (27°F) and averaging around 12°C (55°F), peaking at 26°C (79°F). Both months experience a good amount of precipitation, with May totaling 91 mm (3.6 in) over 13 days and April slightly less at 81 mm (3.2 in) over 10 days. Humidity remains relatively stable, with April at 70% and May slightly lower at 69%. For a closer look at April's climate, you can visit Siena weather in April.

In May, temperatures range from a cool minimum of 3°C (37°F) to a warm maximum of 31°C (89°F), with an average temperature of 16°C (62°F). This month experiences significant precipitation, with about 91 mm (3.6 in) of rain over 13 days and humidity levels averaging 69%. In contrast, June sees a notable rise in temperatures, with a minimum of 9°C (49°F), an average of 22°C (71°F), and a peak of 36°C (96°F). Furthermore, June is much drier, receiving only 38 mm (1.5 in) of rain over just 6 days, and boasts a lower humidity of 62%. For more detailed insights, check out Siena weather in June.

May and July exhibit distinct differences in weather patterns. In May, temperatures can range from a chilly 3°C (37°F) to a warm 31°C (89°F), with an average temperature of 16°C (62°F). This month tends to be wetter, receiving a substantial 91 mm (3.6 in) of precipitation over 13 days and experiencing humidity levels of 69%. In contrast, July offers a much more stable climate, with temperatures ranging from a minimum of 13°C (56°F) to a maximum of 36°C (97°F) and an average of 24°C (76°F). Precipitation in July is significantly lower, with only 38 mm (1.5 in) falling over just 6 days, and humidity dropping to 57%. For a closer look at the weather conditions during this summer month, you can visit Siena weather in July.

May and August present quite contrasting weather patterns. In May, temperatures range from a cool minimum of 3°C (37°F) to a warm maximum of 31°C (89°F), with an average temperature of 16°C (62°F). This month experiences significant precipitation, totaling 91 mm (3.6 in) over about 13 days, coupled with high humidity levels at 69%. In contrast, August boasts a much warmer climate, with temperatures ranging from a minimum of 12°C (53°F) to a maximum of 37°C (99°F), and an average temperature of 25°C (77°F). Precipitation is minimal in August, with only 34 mm (1.3 in) recorded over just 5 days, and the humidity drops to a more comfortable 55%. For more specific details about August weather, you can visit Siena weather in August.

In May, the weather tends to be quite variable, with temperatures ranging from a minimum of 3°C (37°F) to a maximum of 31°C (89°F) and an average of 16°C (62°F). This month experiences around 91 mm (3.6 in) of precipitation, spread over 13 days, along with relatively high humidity at 69%. In contrast, September offers more stable and slightly warmer conditions, with temperatures varying from a minimum of 7°C (45°F) to a maximum of 32°C (90°F) and an average of 20°C (69°F). With 84 mm (3.3 in) of precipitation over just 9 days and a humidity level of 66%, September is typically drier and more comfortable than May. For more information, check out the details linked here: Siena weather in September.

May and October present contrasting yet mild weather experiences. In May, temperatures range from a minim of 3°C (37°F) to a maximum of 31°C (89°F), with an average of 16°C (62°F), marking it as a warm spring month. The humidity sits at 69%, and rainfall occurs over 13 days, resulting in a total precipitation of 91 mm (3.6 in). In contrast, October features slightly cooler temperatures, with a minimum of 5°C (40°F) and a maximum of 27°C (81°F), alongside an average temperature of 15°C (59°F). The humidity rises to 79%, and while it also sees 91 mm of precipitation, it experiences only 8 rainy days, making October a bit drier overall. For more details, you can check out Siena weather in October.

May and November present strikingly different weather conditions. In May, temperatures range from a minimum of 3°C (37°F) to a maximum of 31°C (89°F), with an average of 16°C (62°F). The month enjoys moderate rainfall, with a total of 91 mm (3.6 in) spread over approximately 13 days, and humidity levels around 69%. In contrast, November sees much cooler temperatures, dipping down to a minimum of -3°C (27°F) and averaging 11°C (51°F), with a maximum of 19°C (66°F). It is also a wetter month, receiving 148 mm (5.8 in) of precipitation over about 15 days and a noticeable increase in humidity at 84%. For more insights into the weather during this time, you can check Siena weather in November.

May and December present quite contrasting weather patterns. In May, temperatures range from a minimum of 3°C (37°F) to a maximum of 31°C (89°F), with an average of 16°C (62°F), making it a warm spring month. There tends to be moderate precipitation of 91 mm (3.6 in) over 13 days, along with a humidity level of 69%. In contrast, December has colder temperatures, with a minimum of -4°C (25°F) and a maximum of 16°C (61°F), averaging just 7°C (44°F). Precipitation slightly increases to 98 mm (3.8 in) over 11 days, and humidity rises to 83%. For more details on the weather in December, you can check Siena weather in December.

Compare Siena's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in Siena

As May graces Siena, it brings a delightful shift in weather, marking the transition from the cooler spring months to the warmth of summer. Temperatures begin to climb, making the average feel pleasantly mild compared to the chill of earlier months, while the maximum highs flirt with the 30s°C. Despite the increase in warmth, visitors can expect sporadic rainfall—averaging about 13 days—which nourishes the lush landscapes and contributes to the enchanting beauty of the region. Humidity settles at a moderate 69%, ensuring a comfortable experience for those exploring the vibrant streets and rich history of Siena. For a deeper understanding of what to expect throughout the year, check out Siena Climate.