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
September in Riihimäki brings a decrease in the average high-temperature, falling from August's pleasant 20.8°C (69.4°F) to a mild 15.2°C (59.4°F). Riihimäki's nighttime temperature in September falls to an average of 8.3°C (46.9°F).Humidity
In Riihimäki, the average relative humidity in September is 83%.Rainfall
In September, in Riihimäki, the rain falls for 10.3 days. Throughout September, 20mm (0.79") of precipitation is accumulated. Throughout the year, in Riihimäki, there are 117.8 rainfall days, and 373mm (14.69") of precipitation is accumulated.Snowfall
In Riihimäki, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 53min.On the first day of September in Riihimäki, sunrise is at 06:15 and sunset at 20:26. On the last day of the month, sunrise is at 07:25 and sunset at 18:55 EEST.
Sunshine
In Riihimäki, the average sunshine in September is 6.9h.UV index
In Riihimäki, the average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for the ordinary person.Note: A maximum high daily UV index of 3 during September translates into the following directions:
Exercise prevention - Warding off sunburn is urged. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Take warning! The intensity of the Sun's UV radiation can be nearly amplified twice due to snow reflection.
Frequently asked questions
What are the temperatures in Riihimäki in September?
What is the average humidity in September in Riihimäki?
How much does it rain in Riihimäki in September?
When it does not snow in Riihimäki?
Does it snow in Riihimäki in September?
How many hours of daylight does Riihimäki have in September?
What time are sunrise and sunset in September in Riihimäki?
How many hours of sunshine does Riihimäki have in September?
What is the UV index reading in September in Riihimäki?
Average temperature in September
Riihimäki, Finland
- Average high temperature in September: 15.2°C
The warmest month (with the highest average high temperature) is July (22.2°C).
The month with the lowest average high temperature is January (-3.8°C).
- Average low temperature in September: 8.3°C
The month with the highest average low temperature is July (12.4°C).
The coldest month (with the lowest average low temperature) is January (-8.3°C).
Average pressure in September
Riihimäki, Finland
- Average pressure in September: 1013.2mbar
The month with the highest atmospheric pressure is May (1014.9mbar).
The month with the lowest atmospheric pressure is December (1008.3mbar).
Average wind speed in September
Riihimäki, Finland
- Average wind speed in September: 10km/h
The windiest month (with the highest average wind speed) is December (11.4km/h).
The calmest month (with the lowest average wind speed) is August (9.1km/h).
Average humidity in September
Riihimäki, Finland
- Average humidity in September: 83%
The month with the highest relative humidity is February (95%).
The month with the lowest relative humidity is May (67%).
Average rainfall in September
Riihimäki, Finland
- Average rainfall in September: 20mm
The wettest month (with the highest rainfall) is December (44mm).
The driest month (with the least rainfall) is August (18mm).
Average rainfall days in September
Riihimäki, Finland
- Average rainfall days in September: 10.3 days
The month with the highest number of rainy days is November (13.5 days).
The month with the least rainy days is February (4.2 days).
Average snowfall in September
Riihimäki, Finland
- Average snowfall in September: 0mm
The month with the highest snowfall is February (229mm).
The months with the least snowfall are June, July, August and September (0mm).
Average snowfall days in September
Riihimäki, Finland
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (22.2 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Riihimäki, Finland
- Average daylight in September: 12h and 5min
The month with the longest days is June (Average daylight: 19h and 0min).
The month with the shortest days is December (Average daylight: 5h and 48min).
- Average sunshine in September: 6h and 5min
The month with the most sunshine is June (Average sunshine: 11h and 42min).
The month with the least sunshine is December (Average sunshine: 1h and 30min).
Average sunshine days in September
Riihimäki, Finland
- Average sunshine days in September: 17.8 days
The month with the most sunshine days is June (20.8 days).
The month with the least sunshine days is February (6.5 days).
Average UV index in September
Riihimäki, Finland
- Average UV index in September: 3
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 1).
Average cloud cover in September
Riihimäki, Finland
- Average cloud cover in September: 55
The months with the most cloud cover are January and February (Cloud cover 78).
The month with the least cloud cover is August (Cloud cover 42).
Average visibility in September
Riihimäki, Finland
- Average visibility in September: 8km
The months with the highest visibility are May, June and July (9km).
The months with the lowest visibility are January and February (5km).
Riihimäki, Finland
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