September weather forecastGrenchen, Switzerland
September
Weather in September
September, the first month of the autumn in Grenchen, is still a refreshing month, with an average temperature ranging between max 18.7°C (65.7°F) and min 8.3°C (46.9°F).Temperature
September's onset brings a negligible change in high-temperatures, falling from a warm 23°C (73.4°F) in August to a refreshing 18.7°C (65.7°F). The average low-temperature, in September, is a chilly 8.3°C (46.9°F).Humidity
In Grenchen, the average relative humidity in September is 82%.Rainfall
September is the month with the least rainfall. Rain falls for 15 days and accumulates 46mm (1.81") of precipitation.Snowfall
Months with snowfall in Grenchen are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 1mm (0.04") of snow. In Grenchen, during the entire year, snow falls for 37.6 days and aggregates up to 557mm (21.93") of snow.Daylight
In September, the average length of the day is 12h and 34min.On the first day of the month, sunrise is at 06:50 and sunset at 20:10. On the last day of September, sunrise is at 07:28 and sunset at 19:11 CEST.
Sunshine
In September, the average sunshine is 8.6h.UV index
In Grenchen, the average daily maximum UV index in September is 4. A UV Index value 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 4 during September leads to these instructions:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Grenchen, Switzerland
- Average high temperature in September: 18.7°C
The warmest month (with the highest average high temperature) is July (23.1°C).
The month with the lowest average high temperature is January (2.7°C).
- Average low temperature in September: 8.3°C
The month with the highest average low temperature is July (11.9°C).
The coldest months (with the lowest average low temperature) are January and February (-2.8°C).
Average pressure in September
Grenchen, Switzerland
- Average pressure in September: 1018.6mbar
The month with the highest atmospheric pressure is December (1021mbar).
The month with the lowest atmospheric pressure is April (1015.6mbar).
Average wind speed in September
Grenchen, Switzerland
- Average wind speed in September: 7.2km/h
The windiest month (with the highest average wind speed) is February (10.2km/h).
The calmest month (with the lowest average wind speed) is August (6.3km/h).
Average humidity in September
Grenchen, Switzerland
- Average humidity in September: 82%
The month with the highest relative humidity is January (87%).
The months with the lowest relative humidity are April, July and August (79%).
Average rainfall in September
Grenchen, Switzerland
- Average rainfall in September: 46mm
The wettest month (with the highest rainfall) is June (97mm).
The driest month (with the least rainfall) is September (46mm).
Average rainfall days in September
Grenchen, Switzerland
- Average rainfall days in September: 15 days
The month with the highest number of rainy days is May (21.9 days).
The month with the least rainy days is February (12.3 days).
Average snowfall in September
Grenchen, Switzerland
- Average snowfall in September: 1mm
The month with the highest snowfall is February (133mm).
The months with the least snowfall are June, July and August (0mm).
Average snowfall days in September
Grenchen, Switzerland
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (9.6 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Grenchen, Switzerland
- Average daylight in September: 12h and 36min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in September: 8h and 36min
The month with the most sunshine is August (Average sunshine: 10h and 18min).
The month with the least sunshine is December (Average sunshine: 4h and 54min).
Average sunshine days in September
Grenchen, Switzerland
- Average sunshine days in September: 12.1 days
The month with the most sunshine days is October (14.1 days).
The month with the least sunshine days is May (6.7 days).
Average UV index in September
Grenchen, Switzerland
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Grenchen, Switzerland
- Average cloud cover in September: 37
The months with the most cloud cover are January, February and December (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Grenchen, Switzerland
- Average visibility in September: 8km
The months with the highest visibility are March, April, July and August (9km).
The months with the lowest visibility are January, February, May, June, September, October, November and December (8km).
