Measurements:
°C
°F
Lake Geneva
-8°F
NE 11 mph
Feels like: -22°F
Precip: 0%
World Resorts USA Lake Geneva Weather September Weather in Lake Geneva

Lake Geneva Weather: September

Average Day Temperature: 76.2°F
Average Night Temperature: 59.0°F
Sea Water Temperature: 50.2°F
Number of Sunny Days: 15 days
Sunshine Hours: 11.8 - 13.1 hours
Number of Rainy Days: 1 day
Precipitation Totals: 0.8 in

Air Temperature in September, °F

Select Year: 2025 2024 2023

The highest day temperature in September 2025 was 90°F. The lowest night temperature was 35°F. The average values for day and night temperatures during September were 77.9°F и 55.6°F respectivly.

Lake Geneva Water Sea Temperature in September, °F

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Lake Geneva was 30.0°F. The maximum and minimum values were 30.0°F and 30.0°F respectively.

Sunny, Cloudy and Gloomy days

Most of the days in September are sunny but you can also expect cloudy and gloomy days.

Precipitation Totals in September, in

Precipitation total in September for Lake Geneva is 0.8 in.

Wind Speed in September, mph

The average wind speed in September is 8.3 mph. It makes September one of the most windless months of the year for Lake Geneva.

Average Sunny Hours Per Day

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Lake Geneva in September is 8.2 hours.

Best Time to Visit Lake Geneva
The most sunny months:
September 15 days
October 13 days
August 13 days
The most warm months:
July 82.2 °F
August 81.7 °F
June 78.7 °F
Warmest sea temperature:
August 51.2 °F
October 45.6 °F
July 42.8 °F
The most cold months:
January 24.4 °F
February 27.6 °F
December 32.8 °F
The most rainy months:
April 3 days
May 3 days
June 2 days
The most windy months:
March 11 mph
April 11 mph
November 11 mph

Lake Geneva on the Weather Map

USA Resorts:
NAME
Chicago -2
Hawaii +78
Honolulu +78
Houston +44
Las Vegas +40
Los Angeles +52
Maui +72
Miami +72
Miami Beach +80
New York +18
San Diego +54
San Francisco +46
Sarasota +62
Tampa +62
Washington +28
24 Hours Weather Forecast
Lake Geneva
Local time: 02:10
05 dec, friday
0300 -8°F
NE
11 mph
0600 2°F
NE
11 mph
0900 10°F
NE
11 mph
1200 20°F
NE
14 mph
1500 24°F
NE
14 mph
1800 24°F
NE
13 mph
2100 26°F
NE
13 mph
06 dec, saturday
0000 26°F
E
14 mph