September weather forecast
Twann, Switzerland

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September

Weather in September

September, the first month of the autumn in Twann, 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 witnesses a gentle descent in average high-temperature, descending from August's moderately hot 23°C (73.4°F) to an enjoyable 18.7°C (65.7°F). During September, Twann records a consistent average nighttime temperature of 8.3°C (46.9°F).

Humidity

In September, the average relative humidity in Twann, Switzerland, is 82%.

Rainfall

September is the month with the least rainfall in Twann, Switzerland. Rain falls for 15 days and accumulates 46mm (1.81") of precipitation.

Snowfall

Months with snowfall 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. Throughout the year, in Twann, Switzerland, there are 37.6 snowfall days, and 557mm (21.93") of snow is accumulated.

Daylight

In Twann, the average length of the day in September is 12h and 34min.
On the first day of the month, sunrise is at 06:51 and sunset at 20:11. On the last day of September, in Twann, sunrise is at 07:29 and sunset at 19:12 CEST.

Sunshine

In September, the average sunshine in Twann is 8.6h.

UV index

The average daily maximum UV index in September in Twann is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.
Note: In September, the maximum UV index of 4 suggests this advice:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. UV radiation from the Sun is most dangerous during midday; take precautions and seek shade. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
Updated: Feb 4, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in Twann in September?
An average high-temperature, in September, in Twann, is 18.7°C (65.7°F) and the average low-temperature is 8.3°C (46.9°F).
What is the average humidity in September in Twann?
The average relative humidity in September is 82%.
What is the driest month in Twann?
September is the month with the least rainfall. Rain falls for 15 days and accumulates 46mm (1.81") of precipitation.
How many days does it rain in September in Twann?
In Twann, Switzerland, in September, during 15 rainfall days, 46mm (1.81") of precipitation is typically accumulated.
When does it start snowing in Twann?
September is the first month it typically snows in Twann. Throughout September, in the average 0.1 snowfall days, it receives 1mm (0.04") of snow.
What is the average length of the day in September in Twann?
In Twann, Switzerland, the average day length in September is 12h and 34min.
When are sunrise and sunset in September in Twann?
In September, on the first day of the month, sunrise is at 06:51 and sunset at 20:11. On the last day of the month, in Twann, Switzerland, sunrise is at 07:29 and sunset at 19:12 CEST.
How many hours of sunshine does Twann have in September?
In Twann, the average sunshine duration in September is 8.6h.
What is the UV index intensity in September in Twann?
The average daily maximum UV index in September in Twann is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unsafe exposure to Sun's UV rays.
Today
Tomorrow
Long-term
YearJFMAMJJASeptemberOND
Aug
September
Oct
Average high temperature
23°C
18.7°C
13.7°C
Average low temperature
11.7°C
8.3°C
4.9°C
Average pressure
1017.7mbar
1018.6mbar
1018.5mbar
Average wind speed
6.3km/h
7.2km/h
7.2km/h
Average max. wind speed
7km/h
7.7km/h
8km/h
Average wind speed gusts
10km/h
11.7km/h
12.1km/h
Average humidity
79%
82%
83%
Average rainfall
90mm
46mm
62mm
Average rainfall days
17.8
15
13.6
Average snowfall
0mm
1mm
10mm
Average snowfall days
0
0.1
0.4
Average daylight
14h 1min
12h 4min
10h 5min
Average sunshine
10h 2min
8h 4min
6h 2min
Average sunshine days
9.8
12.1
14.1
Average UV index
4
4
3
Average cloud cover
32%
37%
40%
Average visibility
9km
8km
8km
Average temperature in September
Twann, 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
Twann, 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
Twann, 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
Twann, 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
Twann, 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
Twann, 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
Twann, 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
Twann, 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
Twann, Switzerland
  • Average daylight in September: 12h and 4min

The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).

  • Average sunshine in September: 8h and 4min

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
Twann, 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
Twann, 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
Twann, 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
Twann, 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).

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