September weather forecastHeidelberg, Germany
September
Weather in September
September acts as the harbinger of autumn in Heidelberg. With the city bidding farewell to summer, a refreshing change in weather emerges, cooling the heated air. The decrease in daytime temperature makes the month an excellent time to explore without worrying excessively about weather conditions. The climate makes a significant downward leap from August, with a high temperature of 20.6°C (69.1°F). As the leaves start turning their colors, Heidelberg introduces a picturesque fall scenery, surpassing the summer vibrancy.Temperature
The onset of September is marked by a decrease in temperature, transitioning from a moderately hot 25.8°C (78.4°F) in August to an agreeable 20.6°C (69.1°F). In September, in Heidelberg, Germany, the average low-temperature is a fresh 11.4°C (52.5°F).Humidity
The average relative humidity in September is 72%.Rainfall
In Heidelberg, Germany, in September, it is raining for 10.8 days, with typically 28mm (1.1") of accumulated precipitation. In Heidelberg, Germany, during the entire year, the rain falls for 164.2 days and collects up to 434mm (17.09") of precipitation.Snowfall
April through September are months without snowfall in Heidelberg.Daylight
The average length of the day in September is 12h and 36min.On the first day of the month, sunrise is at 06:42 and sunset at 20:08. On the last day of September, in Heidelberg, sunrise is at 07:24 and sunset at 19:05 CEST.
Sunshine
In Heidelberg, the average sunshine in September is 8.7h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for the average person.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Heidelberg, Germany
- Average high temperature in September: 20.6°C
The warmest month (with the highest average high temperature) is August (25.8°C).
The month with the lowest average high temperature is January (4°C).
- Average low temperature in September: 11.4°C
The month with the highest average low temperature is August (15.3°C).
The coldest month (with the lowest average low temperature) is January (-0.3°C).
Average pressure in September
Heidelberg, Germany
- Average pressure in September: 1018.3mbar
The month with the highest atmospheric pressure is December (1019.1mbar).
The month with the lowest atmospheric pressure is November (1015mbar).
Average wind speed in September
Heidelberg, Germany
- Average wind speed in September: 8.8km/h
The windiest month (with the highest average wind speed) is February (12.3km/h).
The calmest month (with the lowest average wind speed) is August (8.7km/h).
Average humidity in September
Heidelberg, Germany
- Average humidity in September: 72%
The month with the highest relative humidity is January (86%).
The months with the lowest relative humidity are July and August (67%).
Average rainfall in September
Heidelberg, Germany
- Average rainfall in September: 28mm
The wettest month (with the highest rainfall) is May (50mm).
The driest month (with the least rainfall) is April (19mm).
Average rainfall days in September
Heidelberg, Germany
- Average rainfall days in September: 10.8 days
The month with the highest number of rainy days is July (16.4 days).
The month with the least rainy days is September (10.8 days).
Average snowfall in September
Heidelberg, Germany
- Average snowfall in September: 0mm
The month with the highest snowfall is December (44mm).
The months with the least snowfall are April, May, June, July, August and September (0mm).
Average snowfall days in September
Heidelberg, Germany
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (5.4 days).
The months with the least snowfall days are April, May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Heidelberg, Germany
- Average daylight in September: 12h and 36min
The month with the longest days is June (Average daylight: 16h and 12min).
The month with the shortest days is December (Average daylight: 8h and 18min).
- Average sunshine in September: 8h and 42min
The months with the most sunshine are July and August (Average sunshine: 10h and 30min).
The month with the least sunshine is December (Average sunshine: 4h and 6min).
Average sunshine days in September
Heidelberg, Germany
- Average sunshine days in September: 17.3 days
The month with the most sunshine days is September (17.3 days).
The month with the least sunshine days is December (11.5 days).
Average UV index in September
Heidelberg, Germany
- Average UV index in September: 4
The months with the highest UV index are May, 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
Heidelberg, Germany
- Average cloud cover in September: 35
The month with the most cloud cover is December (Cloud cover 59).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in September
Heidelberg, Germany
- Average visibility in September: 9km
The months with the highest visibility are February, March, April, May, June, July, August, September, October and November (9km).
The months with the lowest visibility are January and December (8km).
