September weather forecastNorrtälje, Sweden
September
Weather in September
The arrival of autumn in Norrtälje, Sweden starts to become apparent in September. There is a dip in temperatures and daylight hours, indicating the end of the warm summer. While rain continues to drizzle down with a measure of 25mm (0.98"), the weather begins to cool down. The city starts to display the charming hues of autumn, beckoning a new festive season. It’s the time the city slowly prepares to bid farewell to the picturesque summer.Temperature
September in Norrtälje, Sweden, brings a slight decrease in temperature, down from a comfortable 19.5°C (67.1°F) in August to a mild 15.2°C (59.4°F). In September, Norrtälje's nights cool slightly to a consistent average temperature of 10.9°C (51.6°F).Humidity
In Norrtälje, the average relative humidity in September is 79%.Rainfall
In Norrtälje, in September, during 13.3 rainfall days, 25mm (0.98") of precipitation is typically accumulated. In Norrtälje, during the entire year, the rain falls for 140.1 days and collects up to 354mm (13.94") of precipitation.Snowfall
In Norrtälje, Sweden, snow does not fall in June through September.Daylight
In Norrtälje, the average length of the day in September is 12h and 51min.On the first day of the month, sunrise is at 05:42 and sunset at 19:47. On the last day of September, in Norrtälje, sunrise is at 06:49 and sunset at 18:20 CEST.
Sunshine
The average sunshine in September is 8.3h.UV index
The average daily maximum UV index in September in Norrtälje is 3. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 3 during September translates into the following directions:
Preventative actions are necessary - Recommendations to ward off sunburn are given. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Norrtälje, Sweden
- Average high temperature in September: 15.2°C
The warmest months (with the highest average high temperature) are July and August (19.5°C).
The month with the lowest average high temperature is January (0.2°C).
- Average low temperature in September: 10.9°C
The months with the highest average low temperature are July and August (14.1°C).
The coldest months (with the lowest average low temperature) are January and February (-2.5°C).
Average pressure in September
Norrtälje, Sweden
- 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 (1007.5mbar).
Average wind speed in September
Norrtälje, Sweden
- Average wind speed in September: 17.1km/h
The windiest month (with the highest average wind speed) is December (21.8km/h).
The calmest month (with the lowest average wind speed) is July (14.3km/h).
Average humidity in September
Norrtälje, Sweden
- Average humidity in September: 79%
The months with the highest relative humidity are February and November (86%).
The months with the lowest relative humidity are April, May and June (75%).
Average rainfall in September
Norrtälje, Sweden
- Average rainfall in September: 25mm
The wettest month (with the highest rainfall) is July (52mm).
The driest month (with the least rainfall) is April (16mm).
Average rainfall days in September
Norrtälje, Sweden
- Average rainfall days in September: 13.3 days
The month with the highest number of rainy days is August (16.2 days).
The month with the least rainy days is February (5.8 days).
Average snowfall in September
Norrtälje, Sweden
- Average snowfall in September: 0mm
The month with the highest snowfall is February (82mm).
The months with the least snowfall are June, July, August and September (0mm).
Average snowfall days in September
Norrtälje, Sweden
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Norrtälje, Sweden
- Average daylight in September: 12h and 54min
The month with the longest days is June (Average daylight: 18h and 36min).
The month with the shortest days is December (Average daylight: 6h and 6min).
- Average sunshine in September: 8h and 18min
The month with the most sunshine is June (Average sunshine: 12h and 42min).
The month with the least sunshine is December (Average sunshine: 2h and 24min).
Average sunshine days in September
Norrtälje, Sweden
- Average sunshine days in September: 13.2 days
The month with the most sunshine days is May (14.5 days).
The month with the least sunshine days is August (11.3 days).
Average UV index in September
Norrtälje, Sweden
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January and February (UV index 1).
Average cloud cover in September
Norrtälje, Sweden
- Average cloud cover in September: 41
The month with the most cloud cover is January (Cloud cover 66).
The month with the least cloud cover is August (Cloud cover 35).
Average visibility in September
Norrtälje, Sweden
- Average visibility in September: 10km
The months with the highest visibility are June, July, August, September and October (10km).
The months with the lowest visibility are January, February, March, April, May, November and December (9km).
