Siena Temperature by Month

Siena in Tuscany, Italy sees significant seasonal temperature differences, with daytime highs between 10°C (50°F) in January and 31°C (88°F) in August, averaging 20°C (68°F) annually. Explore the full monthly breakdown below.

The weather in Siena experiences significant differences between warm and cold seasons, with big shifts in temperature. At night, minimum temperatures range from 18°C (64°F) in August to 2°C (36°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in Siena by month:

Temperatures tend to bottom out between 4 AM and 6 AM, then climb to their daily peak around 3 PM. August, the warmest month, sees 320 hours of sunshine.

The chart below shows the average temperature throughout the year:

Siena's average annual maximum temperature is 20°C (68°F). To put that in context, here's how it compares to a few well-known destinations:

Athens, Greece sits at 23°C (73°F) on average, with hot dry summers and mild winters characteristic of the Mediterranean.

Reykjavík, Iceland averages 9°C (48°F) a year, mild summers by Icelandic standards, but cold winters and frequent wind.

Beijing, China averages 20°C (68°F) annually, but with big seasonal swings, very cold winters and hot summers.

Melbourne, Australia averages 20°C (68°F) annually, known for unpredictable weather, with four seasons sometimes happening in one day.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

For cities and regions with significant elevation, altitude is one of the biggest factors shaping local temperatures. As a rule of thumb, temperatures fall by around 6°C for every 1,000 metres gained, so a city at 2,000 metres will typically be around 12°C cooler than a city at sea level in the same region. Higher ground also tends to see more dramatic day-to-night temperature swings, since thinner air loses heat faster after sunset.

For more on Siena's weather, including monthly rainfall, sunshine hours, and humidity, visit our Siena climate page.