Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
Welcoming September, Siena observes a shift in the average high-temperature, falling from August's hot 30.3°C (86.5°F) to a moderately hot 24.5°C (76.1°F). In Siena, the September nights cool down to an average low of 13.2°C (55.8°F).Humidity
The average relative humidity in September is 72%.Rainfall
In Siena, during September, the rain falls for 9.4 days and regularly aggregates up to 35mm (1.38") of precipitation. Throughout the year, there are 123.6 rainfall days, and 363mm (14.29") of precipitation is accumulated.Snowfall
In Siena, snow does not fall in April through November.Daylight
The average length of the day in September in Siena, Italy, is 12h and 30min.On the first day of September, sunrise is at 06:39 and sunset at 19:49. On the last day of the month, sunrise is at 07:11 and sunset at 18:57 CEST.
Sunshine
In Siena, Italy, the average sunshine in September is 10.4h.UV index
In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for the average person.Note: The maximum UV index of 5 during September leads to these instructions:
Take heed. Individuals of lighter complexion can be burned in less than half an hour. Around midday, solar radiation is most harmful; hence, exposure should be limited. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in Siena in September?
What is the average humidity in September in Siena?
How many days does it rain in September in Siena?
When it does not snow in Siena?
How many hours of daylight does Siena have in September?
What time are sunrise and sunset in September in Siena?
How many hours of sunshine does Siena have in September?
How high is the UV index in September in Siena?
Average temperature in September
Siena, Italy
- Average high temperature in September: 24.5°C
The warmest month (with the highest average high temperature) is August (30.3°C).
The month with the lowest average high temperature is January (8.5°C).
- Average low temperature in September: 13.2°C
The month with the highest average low temperature is August (16.3°C).
The coldest month (with the lowest average low temperature) is January (1.9°C).
Average pressure in September
Siena, Italy
- Average pressure in September: 1015.5mbar
The month with the highest atmospheric pressure is December (1018.4mbar).
The month with the lowest atmospheric pressure is July (1013.5mbar).
Average wind speed in September
Siena, Italy
- Average wind speed in September: 8km/h
The windiest months (with the highest average wind speed) are February and March (10.8km/h).
The calmest month (with the lowest average wind speed) is June (7.1km/h).
Average humidity in September
Siena, Italy
- Average humidity in September: 72%
The month with the highest relative humidity is November (85%).
The month with the lowest relative humidity is August (63%).
Average rainfall in September
Siena, Italy
- Average rainfall in September: 35mm
The wettest month (with the highest rainfall) is November (50mm).
The driest month (with the least rainfall) is August (14mm).
Average rainfall days in September
Siena, Italy
- Average rainfall days in September: 9.4 days
The month with the highest number of rainy days is May (13.5 days).
The month with the least rainy days is August (5.8 days).
Average snowfall in September
Siena, Italy
- Average snowfall in September: 0mm
The month with the highest snowfall is February (20mm).
The months with the least snowfall are April, May, June, July, August, September, October and November (0mm).
Average snowfall days in September
Siena, Italy
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (1.4 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Siena, Italy
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 10h and 2min
The months with the most sunshine are July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 5h and 18min).
Average sunshine days in September
Siena, Italy
- Average sunshine days in September: 18.9 days
The month with the most sunshine days is August (23.9 days).
The month with the least sunshine days is February (14.6 days).
Average UV index in September
Siena, Italy
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 2).
Average cloud cover in September
Siena, Italy
- Average cloud cover in September: 23
The months with the most cloud cover are January, February and November (Cloud cover 44).
The month with the least cloud cover is August (Cloud cover 13).
Average visibility in September
Siena, Italy
- Average visibility in September: 9km
The months with the highest visibility are February, March, April, May, June, July, August, September and December (9km).
The months with the lowest visibility are January, October and November (8km).
Siena, Italy
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