The best times to visit Siena for ideal weather are
May 7th to October 14th
based on average temperature and humidity from NOAA (the National Oceanic and Atmospheric Administration). Read below for more weather and travel details.
Siena Travel Guide
Other Siena Travel Info
Weather in Siena
Average temperatures in Siena vary greatly. Considering humidity, temperatures feel cold for about half of the year and otherwise nice with a fair chance of precipitation about half of the year. The area is less temperate than some — in the 34th percentile for pleasant weather — compared to tourist destinations worldwide. Weeks with ideal weather are listed above. If you’re looking for the very warmest time to visit Siena, the hottest months are July, August, and then June. See average monthly temperatures below. The warmest time of year is generally mid July where highs are regularly around 90.8°F (32.7°C) with temperatures rarely dropping below 60.9°F (16.1°C) at night.
Siena Temperatures (Fahrenheit)
Siena Temperatures (Celsius)
The way we experience weather isn’t all about temperature. Higher temperatures affect us much more at higher humidity, and colder temperatures feel piercing with high winds. Our perceived temperatures factor in humidity and wind chill to better represent how hot or cold the day feels to a person.
Siena Perceived Temperature (F)
Siena Perceived Temperature (C)
Average Siena Temperatures by Month
Daily highs (averaged for the month) usually give the best indication of the weather. A significantly lower mean and low generally just means it gets colder at night.
|Month||Avg. High (°F)||Avg. Mean (°F)||Avg. Low (°F)|
|Month||Avg. High (°C)||Avg. Mean (°C)||Avg. Low (°C)|
Precipitation (Rain or Snow)
If dry weather is what you’re after, the months with the lowest chance of significant precipitation in Siena are July, August, and then September. Note that we define “significant precipitation” as .1 inches or more in this section. The lowest chance of rain or snow occurs around mid July. For example, on the week of July 16th there are no days of precipitation on average. By contrast, it’s most likely to rain or snow in early February with an average of 2 days of significant precipitation the week of February 5th.
When can you find snow in Siena? Weather stations report moderate or seasonal snow likely to be deepest around December, especially close to late January and early February. The best time to ski (if at all) in Siena is often around around January 29th when fresh powder is deepest. Please note that a value of 0 for snow in the graph below may either mean there was no snow, or that snow is unreported.
Chance of Precipitation
The graph below shows the % chance of rainy and snowy days in Siena.
Snow on the Ground
The graph below shows the average snow on the ground in Siena (in).
Average Rain and Snow by Month
|Month||Daily Chance of Rain||Average Snow Depth (in)||Total Precipitation (in)|
|Month||Daily Chance of Rain||Average Snow Depth (cm)||Total Precipitation (cm)|
Humidity and Wind
Siena has some very humid months, with other moderately humid months on the other side of the year. The least humid month is July (46.2% relative humidity), and the most humid month is December (75.4%).
Wind in Siena is usually extremely calm. The windiest month is March, followed by February and July. March’s average wind speed of around 3.5 knots (4.1 MPH or 6.6 KPH) is considered “light air.” Maximum sustained winds (the highest speed for the day lasting more than a few moments) are at their highest in early March where average top sustained speeds reach 12 knots, which is considered a moderate breeze.
Relative Humidity (%)
The graph below shows the average % humidity by month in Siena.
The graph below shows wind speed (max and average) in knots.
Average Wind Speeds
Show Wind Speeds
All wind speeds are in knots. 1 knot = 1.15 MPH or 1.85 KPH.
|Month||Avg. Wind||Avg. Wind Feel||Sustained High Wind||High Wind Feel|
|Jan||2.1||Barely noticeable||8.9||Gentle breeze|
|Feb||2.9||Barely noticeable||9.8||Gentle breeze|
|Mar||3.5||Barely noticeable||10.3||Gentle breeze|
|Apr||2.9||Barely noticeable||9.9||Gentle breeze|
|May||2.6||Barely noticeable||9.2||Gentle breeze|
|Jun||2.5||Barely noticeable||9.2||Gentle breeze|
|Jul||2.9||Barely noticeable||10.2||Gentle breeze|
|Aug||2.4||Barely noticeable||9.3||Gentle breeze|
|Sep||2.6||Barely noticeable||9.5||Gentle breeze|
|Oct||2.1||Barely noticeable||8.6||Gentle breeze|
|Nov||2.1||Barely noticeable||8.7||Gentle breeze|
|Dec||2.2||Barely noticeable||9.6||Gentle breeze|
Show Relative Humidity by Month
|Month||Avg. Relative Humidity|
Is it Safe to Travel to Siena?
Our best data indicates this area is generally safe. As of Oct 07, 2019 there are no travel advisories or warnings for Italy; exercise normal security precautions. Check this page for any recent changes or regions to avoid: Travel Advice and Advisories. This advisory was last updated on Aug 22, 2019.
The Busiest and Least Crowded Months
The busiest month for tourism in Siena, Italy is December, followed by May and February. Prices for hotels and flights will be most expensive during these months, though you can save if you purchase well in advance. Tourists are unlikely to visit Siena in August. Those willing to visit at these times will likely find it the least expensive month.
Estimated Tourism by Month
Most Popular Months to Visit
Overall Siena Travel Experience by Season
Spring (March through May)
Humidity and temperatures combine to make this season feel moderate. Highs range from 77.6°F (25.3°C) and 54.6°F (12.6°C) with warmer temperatures in the later months. Rain is somewhat common with 6 to 7 days of significant precipitation per month. Spring is the second busiest for tourism, which makes it a good time for those looking for things to do.
Summer (June through August)
The middle-year months have very comfortable weather with high temperatures that are quite warm. These months see the least precipitation with 3 to 5 days of precipitation per month. June – August is fairly slow season for tourism in Siena, so lodging and other accommodations may cost slightly less.
Fall (September through November)
Fall daily highs range from 82.9°F (28.3°C) and 53.3°F (11.8°C), which will feel comfortable given the humidity and wind. It rains or snows a significant amount: 4 to 7 days per month. Tourism is the slowest during these months due to the weather, so hotels may be affordably priced.
Winter (December through February)
Weather is too cold this time of year in Siena to be enjoyable for warm weather travelers. The average high during this season is between 56.4°F (13.6°C) and 47.2°F (8.4°C). On average, it rains or snows a fair amount: 6 to 7 times per month. These times of year are the busiest with tourists.