September weather forecastAltena, Netherlands
September
Weather in September
September, the first month of the autumn in Altena, is still a comfortable month, with an average temperature fluctuating between 11.7°C (53.1°F) and 18°C (64.4°F).Temperature
A moderate decline in average high-temperatures is noted in September, moving from an agreeable 21.3°C (70.3°F) in August to an enjoyable 18°C (64.4°F). During the month of September, an average temperature of 11.7°C (53.1°F) is noted during the nights.Humidity
In September, the average relative humidity in Altena is 82%.Rainfall
In September, in Altena, Netherlands, the rain falls for 15.1 days. Throughout September, 26mm (1.02") of precipitation is accumulated. In Altena, during the entire year, the rain falls for 179 days and collects up to 336mm (13.23") of precipitation.Snowfall
April through October are months without snowfall in Altena.Daylight
In Altena, the average length of the day in September is 12h and 40min.On the first day of the month, sunrise is at 06:44 and sunset at 20:22. On the last day of September, sunrise is at 07:34 and sunset at 19:13 CEST.
Sunshine
In Altena, the average sunshine in September is 7.2h.UV index
In September, the average daily maximum UV index in Altena, Netherlands, is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the ordinary person.Note: A maximum high UV index of 4 in September translates into the following recommendations:
Be vigilant - Suggestions to stave off sun damage are provided. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Altena, Netherlands
- Average high temperature in September: 18°C
The warmest month (with the highest average high temperature) is August (21.3°C).
The month with the lowest average high temperature is January (4.4°C).
- Average low temperature in September: 11.7°C
The month with the highest average low temperature is August (13.9°C).
The coldest month (with the lowest average low temperature) is February (1°C).
Average pressure in September
Altena, Netherlands
- Average pressure in September: 1016.4mbar
The months with the highest atmospheric pressure are May and September (1016.4mbar).
The month with the lowest atmospheric pressure is November (1011.1mbar).
Average wind speed in September
Altena, Netherlands
- Average wind speed in September: 15.1km/h
The windiest month (with the highest average wind speed) is December (21.2km/h).
The calmest month (with the lowest average wind speed) is July (14km/h).
Average humidity in September
Altena, Netherlands
- Average humidity in September: 82%
The month with the highest relative humidity is December (88%).
The month with the lowest relative humidity is April (77%).
Average rainfall in September
Altena, Netherlands
- Average rainfall in September: 26mm
The wettest month (with the highest rainfall) is June (41mm).
The driest month (with the least rainfall) is April (17mm).
Average rainfall days in September
Altena, Netherlands
- Average rainfall days in September: 15.1 days
The month with the highest number of rainy days is July (18.7 days).
The month with the least rainy days is February (11.5 days).
Average snowfall in September
Altena, Netherlands
- Average snowfall in September: 0mm
The month with the highest snowfall is January (17mm).
The months with the least snowfall are April, May, June, July, August, September and October (0mm).
Average snowfall days in September
Altena, Netherlands
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Altena, Netherlands
- Average daylight in September: 12h and 42min
The month with the longest days is June (Average daylight: 16h and 54min).
The month with the shortest days is December (Average daylight: 7h and 36min).
- Average sunshine in September: 7h and 12min
The month with the most sunshine is July (Average sunshine: 9h and 12min).
The month with the least sunshine is December (Average sunshine: 3h and 24min).
Average sunshine days in September
Altena, Netherlands
- Average sunshine days in September: 10.2 days
The months with the most sunshine days are March and April (14.8 days).
The month with the least sunshine days is December (9 days).
Average UV index in September
Altena, Netherlands
- Average UV index in September: 4
The month with the highest UV index is 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
Altena, Netherlands
- Average cloud cover in September: 46
The month with the most cloud cover is December (Cloud cover 68).
The months with the least cloud cover are April and August (Cloud cover 41).
Average visibility in September
Altena, Netherlands
- Average visibility in September: 9km
The months with the highest visibility are April and August (10km).
The months with the lowest visibility are January, February, March, May, June, July, September, October, November and December (9km).
