September weather forecastDubuque, IA

September
Weather in September
September brings a soothing transition from summer to fall in Dubuque, Iowa. The temperatures witness a moderate drop to 72.5°F (22.5°C) from the August highs, making it an idyllic month for exploring the city and its surroundings. The decreasing daylight hours and changing hues of leaves signal the impending arrival of autumn. Despite the rainfall of 2.6" (66mm), it undoubtedly remains an enjoyable time to relish the outdoor activities. The taste of fall and warm weather make this month a unique time to experience Dubuque's beauty.Temperature
The arrival of September correlates with a minor temperature reduction, down from August's warm 78.6°F (25.9°C) to a pleasant 72.5°F (22.5°C). An average nighttime temperature of 53.2°F (11.8°C) is observed during September.Humidity
The average relative humidity in September is 80%.Rainfall
In Dubuque, in September, it is raining for 11.4 days, with typically 2.6" (66mm) of accumulated precipitation. In Dubuque, during the entire year, the rain falls for 135.3 days and collects up to 27.4" (696mm) of precipitation.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:28 am and sunset at 7:36 pm. On the last day of September, sunrise is at 6:59 am and sunset at 6:45 pm CDT.
Sunshine
In September, the average sunshine is 8.9h.UV index
In Dubuque, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.Note: In September, the maximum UV index of 4 translates into these guidelines:
Take necessary precautions - Protection from skin and eye injury is mandatory. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Dubuque, IA
- Average high temperature in September: 72.5°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is January (25°F).
- Average low temperature in September: 53.2°F
The month with the highest average low temperature is July (62.8°F).
The coldest month (with the lowest average low temperature) is January (12.4°F).
Average pressure in September
Dubuque, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Dubuque, IA
- Average wind speed in September: 7.8mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).
Average humidity in September
Dubuque, IA
- Average humidity in September: 80%
The months with the highest relative humidity are January and February (87%).
The month with the lowest relative humidity is October (76%).
Average rainfall in September
Dubuque, IA
- Average rainfall in September: 2.6"
The wettest months (with the highest rainfall) are May and June (3.7").
The driest months (with the least rainfall) are January and February (1.14").
Average rainfall days in September
Dubuque, IA
- Average rainfall days in September: 11.4 days
The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in September
Dubuque, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.88").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Dubuque, IA
- 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 May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Dubuque, IA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 8h and 54min
The months with the most sunshine are July and August (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in September
Dubuque, IA
- Average sunshine days in September: 17.2 days
The months with the most sunshine days are November and December (17.5 days).
The month with the least sunshine days is June (10.3 days).
Average UV index in September
Dubuque, IA
- Average UV index in September: 4
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, November and December (UV index 1).
Average cloud cover in September
Dubuque, IA
- Average cloud cover in September: 33
The month with the most cloud cover is January (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Dubuque, IA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, August, September, October, November and December (6mi).
The months with the lowest visibility are January and July (5mi).





