September weather forecastLeiden, Netherlands
September
Weather in September
September marks the start of the transition from summer to autumn in Leiden. With temperatures and rainfall dropping to 18.1°C (64.6°F) and 40mm (1.57") respectively, the weather begins to cool. Despite fewer sunshine hours, the beauty of the changing colors of nature provides a visual treat. The wind speed remains similar to August, adding a fresh breeze to the slightly cooler air. The balance between the warm and cool periods makes September a comfortable month for outdoor activities.Temperature
September denotes a minimal variation in the average high-temperature to a comfortable 18.1°C (64.6°F) from August's 21°C (69.8°F). Leiden's average low temperature, barely cooler than the daytime high, steadies at a moderate 13.8°C (56.8°F) during September.Humidity
In September, the average relative humidity in Leiden is 77%.Rainfall
In Leiden, in September, during 15.6 rainfall days, 40mm (1.57") of precipitation is typically accumulated. In Leiden, during the entire year, the rain falls for 183.4 days and collects up to 400mm (15.75") of precipitation.Snowfall
April through October are months without snowfall in Leiden.Daylight
In September, the average length of the day in Leiden is 12h and 39min.On the first day of the month, sunrise is at 06:54 and sunset at 20:29. On the last day of September, in Leiden, sunrise is at 07:42 and sunset at 19:21 CEST.
Sunshine
In September, the average sunshine is 7.1h.UV index
In Leiden, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: In September, a regular UV index of 4 translates into these guidelines:
Take necessary precautions - Defending against sun damage is advocated. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Leiden, Netherlands
- Average high temperature in September: 18.1°C
The warmest month (with the highest average high temperature) is August (21°C).
The month with the lowest average high temperature is January (5.8°C).
- Average low temperature in September: 13.8°C
The month with the highest average low temperature is August (16.3°C).
The coldest month (with the lowest average low temperature) is February (2.8°C).
Average pressure in September
Leiden, Netherlands
- Average pressure in September: 1016.8mbar
The month with the highest atmospheric pressure is September (1016.8mbar).
The month with the lowest atmospheric pressure is November (1011.2mbar).
Average wind speed in September
Leiden, Netherlands
- Average wind speed in September: 17.5km/h
The windiest month (with the highest average wind speed) is December (24.7km/h).
The calmest month (with the lowest average wind speed) is July (16.1km/h).
Average humidity in September
Leiden, Netherlands
- Average humidity in September: 77%
The months with the highest relative humidity are January and December (83%).
The months with the lowest relative humidity are April and August (75%).
Average rainfall in September
Leiden, Netherlands
- Average rainfall in September: 40mm
The wettest month (with the highest rainfall) is August (53mm).
The driest month (with the least rainfall) is April (14mm).
Average rainfall days in September
Leiden, Netherlands
- Average rainfall days in September: 15.6 days
The month with the highest number of rainy days is August (19.1 days).
The month with the least rainy days is April (11.3 days).
Average snowfall in September
Leiden, Netherlands
- Average snowfall in September: 0mm
The month with the highest snowfall is February (22mm).
The months with the least snowfall are April, May, June, July, August, September and October (0mm).
Average snowfall days in September
Leiden, Netherlands
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (3.8 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
Leiden, Netherlands
- Average daylight in September: 12h and 42min
The month with the longest days is June (Average daylight: 16h and 42min).
The month with the shortest days is December (Average daylight: 7h and 48min).
- Average sunshine in September: 7h and 6min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is December (Average sunshine: 3h and 30min).
Average sunshine days in September
Leiden, Netherlands
- Average sunshine days in September: 10.8 days
The month with the most sunshine days is April (16.8 days).
The month with the least sunshine days is December (8.1 days).
Average UV index in September
Leiden, Netherlands
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Leiden, Netherlands
- Average cloud cover in September: 44
The month with the most cloud cover is December (Cloud cover 65).
The months with the least cloud cover are April and August (Cloud cover 38).
Average visibility in September
Leiden, Netherlands
- Average visibility in September: 10km
The months with the highest visibility are February, March, April, May, June, July, August, September, October and November (10km).
The months with the lowest visibility are January and December (9km).
