September weather forecastGrafton, WI
September
Weather in September
September, the first month of the autumn in Grafton, is also an agreeable month, with an average temperature fluctuating between 68.9°F (20.5°C) and 55.9°F (13.3°C).Temperature
With the arrival of September, Grafton experiences a modest decline in average high-temperatures, transitioning from a moderately hot 75.4°F (24.1°C) in August to a pleasant 68.9°F (20.5°C). Grafton's nights in September experience an average temperature drop to a mild 55.9°F (13.3°C).Humidity
In Grafton, the average relative humidity in September is 79%.Rainfall
In Grafton, in September, it is raining for 12.9 days, with typically 2.17" (55mm) of accumulated precipitation. In Grafton, during the entire year, the rain falls for 134.9 days and collects up to 23.94" (608mm) of precipitation.Snowfall
In Grafton, Wisconsin, snow does not fall in May through September.Daylight
In September, the average length of the day is 12h and 29min.On the first day of September, sunrise is at 6:16 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:48 am and sunset at 6:34 pm CDT.
Sunshine
In Grafton, the average sunshine in September is 9.1h.UV index
In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for the average person.Note: In September, the maximum UV index of 4 transforms into these recommendations:
Undertake protective steps - Recommendations to avoid sunburn are issued. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Grafton, WI
- Average high temperature in September: 68.9°F
The warmest month (with the highest average high temperature) is July (76.1°F).
The month with the lowest average high temperature is January (25.5°F).
- Average low temperature in September: 55.9°F
The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is January (15.8°F).
Average pressure in September
Grafton, 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 (29.91"Hg).
Average wind speed in September
Grafton, WI
- Average wind speed in September: 8.9mph
The windiest month (with the highest average wind speed) is January (12.1mph).
The calmest month (with the lowest average wind speed) is July (7.5mph).
Average humidity in September
Grafton, WI
- Average humidity in September: 79%
The month with the highest relative humidity is January (86%).
The months with the lowest relative humidity are April, October and November (77%).
Average rainfall in September
Grafton, WI
- Average rainfall in September: 2.17"
The wettest month (with the highest rainfall) is July (2.99").
The driest month (with the least rainfall) is February (0.98").
Average rainfall days in September
Grafton, WI
- Average rainfall days in September: 12.9 days
The month with the highest number of rainy days is May (15.8 days).
The month with the least rainy days is February (3.8 days).
Average snowfall in September
Grafton, WI
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.43").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Grafton, WI
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Grafton, 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 0min).
- Average sunshine in September: 9h and 6min
The months with the most sunshine are July and August (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in September
Grafton, WI
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is December (16.4 days).
The month with the least sunshine days is July (11.6 days).
Average UV index in September
Grafton, 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, November and December (UV index 1).
Average cloud cover in September
Grafton, WI
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 63).
The months with the least cloud cover are July and August (Cloud cover 28).
Average visibility in September
Grafton, 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).
