September weather forecastWest Allis, WI
September
Weather in September
September marks the cusp of fall in West Allis as temperatures start to moderate from the summer heat to a more pleasant range. The humidity also decreases, making it an ideal time for outdoor exploration and late summer barbecues. Rain remains relatively moderate, balancing the drying effects of the summer. The changing foliage begins to showcase stunning fall colors, introducing a different palette to the cityscape. Despite the shift in weather, outdoor activities remain attractive before the colder months roll in.Temperature
September's arrival comes with a mild decrease in the average high-temperature, moving subtly from a warm 77°F (25°C) in August to a pleasant 70.5°F (21.4°C). Throughout the month of September, West Allis expects an average low of 57.2°F (14°C).Humidity
The average relative humidity in September is 76%.Rainfall
In September, the rain falls for 12.1 days. Throughout September, 1.54" (39mm) of precipitation is accumulated. Throughout the year, in West Allis, there are 126 rainfall days, and 19.37" (492mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September in West Allis is 12h and 29min.On the first day of the month, sunrise is at 6:17 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:49 am and sunset at 6:34 pm CDT.
Sunshine
In September, the average sunshine is 9h.UV index
In West Allis, 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 ordinary individuals.Note: The average daily UV index of 4 in September transforms into the following instructions:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
West Allis, WI
- Average high temperature in September: 70.5°F
The warmest month (with the highest average high temperature) is July (77.9°F).
The month with the lowest average high temperature is January (26.1°F).
- Average low temperature in September: 57.2°F
The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (16.2°F).
Average pressure in September
West Allis, WI
- Average pressure in September: 30.03"Hg
The months with the highest atmospheric pressure are January, February and March (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
West Allis, WI
- Average wind speed in September: 8.5mph
The windiest month (with the highest average wind speed) is January (11.4mph).
The calmest month (with the lowest average wind speed) is July (7.1mph).
Average humidity in September
West Allis, WI
- Average humidity in September: 76%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (75%).
Average rainfall in September
West Allis, WI
- Average rainfall in September: 1.54"
The wettest month (with the highest rainfall) is July (2.56").
The driest months (with the least rainfall) are February and December (0.83").
Average rainfall days in September
West Allis, WI
- Average rainfall days in September: 12.1 days
The month with the highest number of rainy days is July (15.9 days).
The month with the least rainy days is February (3.3 days).
Average snowfall in September
West Allis, WI
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.03").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
West Allis, WI
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
West Allis, WI
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 9h and 0min
The months with the most sunshine are July and August (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in September
West Allis, WI
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is November (17.4 days).
The months with the least sunshine days are July and August (12.7 days).
Average UV index in September
West Allis, 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 and December (UV index 1).
Average cloud cover in September
West Allis, WI
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 64).
The months with the least cloud cover are July and August (Cloud cover 29).
Average visibility in September
West Allis, WI
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
