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.
Siena Monthly Temperatures
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:
Daily Historical Temperatures
50-year average (1976-2025)
Average high and low temperatures for each day of the month based on long-term records.
Average temperatures in July
Historical Siena Temperatures: 1976-2026
Browse day-by-day temperature records for Siena spanning 51 years. Select any month and year to see actual high and low temperatures recorded on each day.
Temperature: Siena vs Italy
The map below shows the annual temperature across Italy. You can also select individual months if you want to compare a specific time of year.
very warm
warm
pleasant
moderate
cold
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Siena vs World: Temperature Compared
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.
