Siena sits in the hills of central Tuscany at 322 metres (1,056 feet) above sea level, giving it a Mediterranean climate with some continental influence. Summers are hot and dry, winters are cool with moderate rainfall, and spring and autumn bring pleasant temperatures ideal for exploring the medieval streets. The city receives about 800mm (31 inches) of rain annually, with October and November being the wettest months. The warmest month is July with average highs of 31°C (88°F), while January is the coldest with average lows of 2°C (36°F). For a detailed look at how the weather affects your trip, see the {u_link(article_links.get(“best_time”, SIENA_LINK + “/” + articles[“best_time”][“slug”] + “/”), “best time to visit Siena guide”)}.
Siena Weather by Month: Temperature & Rainfall Breakdown
The table below shows average high and low temperatures, rainfall, and sunshine hours for each month in Siena. Data is based on 30-year climate normals from the nearest weather station at Siena Ampugnano Airport (SAY), about 9km west of the city centre.
| Month | Avg High | Avg Low | Rainfall (mm) | Sun (hrs/day) | Sea Temp |
|---|---|---|---|---|---|
| January | 10°C / 50°F | 2°C / 36°F | 65 | 4 | N/A |
| February | 11°C / 52°F | 3°C / 37°F | 60 | 5 | N/A |
| March | 14°C / 57°F | 5°C / 41°F | 65 | 6 | N/A |
| April | 17°C / 63°F | 7°C / 45°F | 70 | 7 | N/A |
| May | 22°C / 72°F | 11°C / 52°F | 60 | 8 | N/A |
| June | 27°C / 81°F | 14°C / 57°F | 45 | 10 | N/A |
| July | 31°C / 88°F | 17°C / 63°F | 30 | 11 | N/A |
| August | 30°C / 86°F | 17°C / 63°F | 50 | 10 | N/A |
| September | 26°C / 79°F | 14°C / 57°F | 75 | 8 | N/A |
| October | 20°C / 68°F | 10°C / 50°F | 110 | 6 | N/A |
| November | 14°C / 57°F | 6°C / 43°F | 100 | 4 | N/A |
| December | 10°C / 50°F | 3°C / 37°F | 75 | 3 | N/A |
Siena Weather by Month: Spring (March to May)
Spring is one of the best seasons to visit Siena. March starts cool with highs around 14°C (57°F) and occasional rain showers, but by May temperatures reach a pleasant 22°C (72°F) with 8 hours of daily sunshine. April averages 70mm of rain spread across about 10 days, so pack a light waterproof jacket. The Tuscan countryside turns bright green with wildflowers, and the hills around Siena are covered in poppies by late April. This is also when outdoor cafes begin setting up tables in Piazza del Campo, though evenings still require a sweater until late May when lows finally stay above 10°C (50°F).
Siena Weather by Month: Summer (June to August)
Summer brings hot, dry weather typical of inland Tuscany. July is the hottest month with average highs of 31°C (88°F) and peaks occasionally reaching 36°C (97°F) during heatwaves. Rainfall drops to just 30mm in July (about 4 rainy days), making it the driest month. August is nearly as warm at 30°C (86°F) but sees a slight increase to 50mm of rain from occasional thunderstorms. Humidity is moderate at 55-65%, and with 10-11 hours of sunshine daily, you will want sunscreen, a hat, and plenty of water while walking the steep medieval streets. Most budget accommodations and smaller B&Bs do not have air conditioning , check before booking if visiting in July or August. Many restaurants close for the first two weeks of August for ferie (Italian summer holiday).
Siena Weather by Month: Autumn (September to November)
September remains warm and pleasant with highs of 26°C (79°F) and 8 hours of sunshine, but rainfall increases to 75mm. October brings the most rain of any month (110mm over about 11 days) as Atlantic weather systems arrive. Temperatures drop to highs of 20°C (68°F) in October and 14°C (57°F) by November. The autumn foliage in the Tuscan hills is at its peak from mid-October through early November, and the grape harvest (vendemmia) happens in September and October. November is the second-wettest month at 100mm and can feel damp and grey , it has the fewest visitors of any month and many rural agriturismi close for the season.
Siena Weather by Month: Winter (December to February)
Winters in Siena are cool but not severe. January is the coldest month with average highs of 10°C (50°F) and lows of 2°C (36°F). Snowfall is rare , Siena sees perhaps one or two light snowfalls per winter, and it rarely accumulates on the ground for more than a day. Rainfall averages 60-75mm per month in winter, spread across 8-10 rainy days. December has the fewest sunshine hours at just 3 per day. The Christmas season brings festive lights to Via di Città and Piazza del Campo, and hotel rates drop to their lowest of the year (except for the Christmas and New Year period). Many museums and attractions operate on reduced winter hours, typically closing by 17:00 or 18:00.
