Siena, Italy climate
Cfa Humid subtropical
Siena has a seasonal mild-temperate climate (Humid subtropical, Köppen Cfa). The hottest month is July with an average daily high near 89°F, while the coldest is January averaging around 33°F at night. Around 34 inches of precipitation falls each year, peaking in November (4.8 inches) and easing off in July (1.7 inches).
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Summers
Hot
Highs near 89°F in July.
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Winters
Chilly
Lows near 33°F in January.
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Rain
Moderate rainfall
About 34 in of rain a year.
Wettest in November
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Sky & trend
Partly cloudy
A roughly even mix of sun and cloud.
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresHours of sunshine per day
Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)Siena climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 49 | 52 | 59 | 66 | 74 | 82 | 89 | 89 | 78 | 68 | 57 | 50 |
| Avg temp (°F) | 40 | 42 | 48 | 54 | 62 | 69 | 74 | 74 | 65 | 57 | 49 | 42 |
| Avg low (°F) | 33 | 33 | 37 | 42 | 49 | 56 | 60 | 60 | 53 | 47 | 41 | 34 |
| Precipitation (in) | 2.1 | 2.2 | 2.5 | 2.8 | 2.9 | 2.1 | 1.7 | 1.7 | 3.8 | 4.3 | 4.8 | 3.2 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°F) | 49 | 52 | 59 | 66 | 74 | 82 |
| Avg temp (°F) | 40 | 42 | 48 | 54 | 62 | 69 |
| Avg low (°F) | 33 | 33 | 37 | 42 | 49 | 56 |
| Precipitation (in) | 2.1 | 2.2 | 2.5 | 2.8 | 2.9 | 2.1 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°F) | 89 | 89 | 78 | 68 | 57 | 50 |
| Avg temp (°F) | 74 | 74 | 65 | 57 | 49 | 42 |
| Avg low (°F) | 60 | 60 | 53 | 47 | 41 | 34 |
| Precipitation (in) | 1.7 | 1.7 | 3.8 | 4.3 | 4.8 | 3.2 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 65 | 61 | 62 | 65 | 62 | 50 | 36 | 39 | 53 | 62 | 69 | 65 |
| Relative humidity (%) | 91 | 86 | 82 | 78 | 73 | 63 | 54 | 55 | 68 | 80 | 89 | 91 |
| Wind speed (mph) | 5.4 | 5.8 | 6.0 | 5.3 | 4.8 | 4.5 | 4.7 | 4.4 | 4.7 | 4.9 | 5.2 | 5.4 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 65 | 61 | 62 | 65 | 62 | 50 |
| Relative humidity (%) | 91 | 86 | 82 | 78 | 73 | 63 |
| Wind speed (mph) | 5.4 | 5.8 | 6.0 | 5.3 | 4.8 | 4.5 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 36 | 39 | 53 | 62 | 69 | 65 |
| Relative humidity (%) | 54 | 55 | 68 | 80 | 89 | 91 |
| Wind speed (mph) | 4.7 | 4.4 | 4.7 | 4.9 | 5.2 | 5.4 |
Methodology & sources
Temperature & precipitation — the official 1991–2020 climate normals from the WMO's CLINO 1991–2020 collection, measured at Arezzo, about 45 km from the city centre.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.