September weather forecastLewis, WI
September
Weather in September
September, the first month of the autumn in Lewis, is also an agreeable month, with an average temperature varying between 50.2°F (10.1°C) and 68.9°F (20.5°C).Temperature
The move into September indicates a slight reduction in the average high-temperature, down from August's moderately hot 76.1°F (24.5°C) to a pleasant 68.9°F (20.5°C). An average low-temperature of 50.2°F (10.1°C) is noted in Lewis during the month of September.Humidity
In Lewis, Wisconsin, the average relative humidity in September is 79%.Rainfall
In Lewis, Wisconsin, during September, the rain falls for 13.9 days and regularly aggregates up to 1.61" (41mm) of precipitation. Throughout the year, there are 122.5 rainfall days, and 20.87" (530mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall in Lewis.Daylight
The average length of the day in September in Lewis is 12h and 31min.On the first day of September in Lewis, sunrise is at 6:31 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 6:51 pm CDT.
Sunshine
In September, the average sunshine is 8.4h.UV index
In Lewis, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for average individuals.Note: In September, the maximum UV index of 4 transforms into these recommendations:
Exercise caution. Those with pale skin may experience burns in less than half an hour. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Lewis, WI
- Average high temperature in September: 68.9°F
The warmest month (with the highest average high temperature) is July (78.1°F).
The month with the lowest average high temperature is January (17.8°F).
- Average low temperature in September: 50.2°F
The month with the highest average low temperature is July (59.5°F).
The coldest month (with the lowest average low temperature) is January (4.8°F).
Average pressure in September
Lewis, WI
- Average pressure in September: 30"Hg
The month with the highest atmospheric pressure is February (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Lewis, WI
- Average wind speed in September: 8.1mph
The windiest month (with the highest average wind speed) is April (9.6mph).
The calmest month (with the lowest average wind speed) is July (6.9mph).
Average humidity in September
Lewis, WI
- Average humidity in September: 79%
The month with the highest relative humidity is January (92%).
The months with the lowest relative humidity are April and May (76%).
Average rainfall in September
Lewis, WI
- Average rainfall in September: 1.61"
The wettest month (with the highest rainfall) is June (3.35").
The driest month (with the least rainfall) is January (0.59").
Average rainfall days in September
Lewis, WI
- Average rainfall days in September: 13.9 days
The month with the highest number of rainy days is June (16.8 days).
The month with the least rainy days is January (2.3 days).
Average snowfall in September
Lewis, WI
- Average snowfall in September: 0"
The month with the highest snowfall is December (5.47").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Lewis, WI
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (17.3 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Lewis, WI
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in September: 8h and 24min
The month with the most sunshine is July (Average sunshine: 9h and 36min).
The month with the least sunshine is January (Average sunshine: 2h and 36min).
Average sunshine days in September
Lewis, WI
- Average sunshine days in September: 14.3 days
The month with the most sunshine days is October (16.3 days).
The month with the least sunshine days is June (10.3 days).
Average UV index in September
Lewis, WI
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
Lewis, WI
- Average cloud cover in September: 39
The month with the most cloud cover is January (Cloud cover 74).
The month with the least cloud cover is July (Cloud cover 35).
Average visibility in September
Lewis, WI
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, September, October and November (6mi).
The months with the lowest visibility are January, February and December (4mi).





