September weather forecastPosio, Finland
September
Weather in September
September, the first month of the autumn in Posio, is still a cool month, with an average temperature varying between 4.8°C (40.6°F) and 10.7°C (51.3°F).Temperature
As September begins, there is a decrease in the average high-temperature, falling from a comfortable 16.6°C (61.9°F) in August to a cool 10.7°C (51.3°F). Posio, in September, observes a steady average low-temperature of 4.8°C (40.6°F).Humidity
In Posio, the average relative humidity in September is 87%.Rainfall
In Posio, Finland, in September, it is raining for 15.4 days, with typically 38mm (1.5") of accumulated precipitation. Throughout the year, there are 117.1 rainfall days, and 485mm (19.09") of precipitation is accumulated.Snowfall
Months with snowfall are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 1.5 snowfall days, it receives 6mm (0.24") of snow. In Posio, during the entire year, snow falls for 154.7 days and aggregates up to 1613mm (63.5") of snow.Daylight
In September, the average length of the day is 13h and 7min.On the first day of the month, sunrise is at 05:44 and sunset at 20:30. On the last day of September, in Posio, sunrise is at 07:16 and sunset at 18:37 EEST.
Sunshine
The average sunshine in September is 5.2h.UV index
In September, the average daily maximum UV index is 2. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 2 in September converts into the following recommendations:
Babies, children, and individuals with sensitive skin should always have protection against extended sun exposure. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Posio, Finland
- Average high temperature in September: 10.7°C
The warmest month (with the highest average high temperature) is July (19.2°C).
The month with the lowest average high temperature is January (-8.4°C).
- Average low temperature in September: 4.8°C
The month with the highest average low temperature is July (10.3°C).
The coldest month (with the lowest average low temperature) is January (-13.8°C).
Average pressure in September
Posio, Finland
- Average pressure in September: 1011.5mbar
The month with the highest atmospheric pressure is May (1014.4mbar).
The month with the lowest atmospheric pressure is December (1006.1mbar).
Average wind speed in September
Posio, Finland
- Average wind speed in September: 11.7km/h
The windiest month (with the highest average wind speed) is November (12.9km/h).
The calmest month (with the lowest average wind speed) is July (10.5km/h).
Average humidity in September
Posio, Finland
- Average humidity in September: 87%
The month with the highest relative humidity is January (97%).
The month with the lowest relative humidity is June (70%).
Average rainfall in September
Posio, Finland
- Average rainfall in September: 38mm
The wettest month (with the highest rainfall) is July (57mm).
The driest months (with the least rainfall) are January and April (31mm).
Average rainfall days in September
Posio, Finland
- Average rainfall days in September: 15.4 days
The month with the highest number of rainy days is August (18.4 days).
The month with the least rainy days is February (1.3 days).
Average snowfall in September
Posio, Finland
- Average snowfall in September: 6mm
The month with the highest snowfall is December (283mm).
The months with the least snowfall are July and August (0mm).
Average snowfall days in September
Posio, Finland
- Average snowfall days in September: 1.5 days
The month with the highest number of snowfall days is December (24.5 days).
The month with the least snowfall days is July (0 days).
Average daylight in September /
Average sunshine in September
Posio, Finland
- Average daylight in September: 13h and 6min
The month with the longest days is July (Average daylight: 20h and 18min).
The month with the shortest days is December (Average daylight: 3h and 6min).
- Average sunshine in September: 5h and 12min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is December (Average sunshine: 0h and 42min).
Average sunshine days in September
Posio, Finland
- Average sunshine days in September: 10.5 days
The month with the most sunshine days is July (11.6 days).
The month with the least sunshine days is April (5.3 days).
Average UV index in September
Posio, Finland
- Average UV index in September: 2
The months with the highest UV index are June, July and August (UV index 4).
The months with the lowest UV index are January, February, March, April, October, November and December (UV index 1).
Average cloud cover in September
Posio, Finland
- Average cloud cover in September: 68
The month with the most cloud cover is February (Cloud cover 85).
The month with the least cloud cover is July (Cloud cover 51).
Average visibility in September
Posio, Finland
- Average visibility in September: 7km
The months with the highest visibility are June and July (9km).
The months with the lowest visibility are January, February, March, April and December (5km).





