September weather forecastRiverside, IA
September
Weather in September
September, the first month of the autumn in Riverside, is still a warm month, with an average temperature fluctuating between 75.4°F (24.1°C) and 56.3°F (13.5°C).Temperature
Start of September brings a slight shift in the average high-temperature, dipping a bit from August's warm 81.1°F (27.3°C) to a still moderately hot 75.4°F (24.1°C). During September, Riverside experiences a consistent low-temperature average of 56.3°F (13.5°C).Humidity
In September, the average relative humidity in Riverside is 76%.Rainfall
In September, the rain falls for 12.5 days. Throughout September, 2.64" (67mm) of precipitation is accumulated. Throughout the year, in Riverside, there are 144.7 rainfall days, and 30.16" (766mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall in Riverside.Daylight
The average length of the day in September in Riverside is 12h and 28min.On the first day of the month, sunrise is at 6:33 am and sunset at 7:38 pm. On the last day of September, in Riverside, sunrise is at 7:02 am and sunset at 6:49 pm CDT.
Sunshine
In September, the average sunshine is 9.3h.UV index
In Riverside, Iowa, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: The daily high UV index of 4 in September translates into this advice:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Riverside, IA
- Average high temperature in September: 75.4°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (28.4°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (16.2°F).
Average pressure in September
Riverside, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Riverside, IA
- Average wind speed in September: 7.9mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (6.9mph).
Average humidity in September
Riverside, IA
- Average humidity in September: 76%
The months with the highest relative humidity are January and July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Riverside, IA
- Average rainfall in September: 2.64"
The wettest month (with the highest rainfall) is May (4.45").
The driest month (with the least rainfall) is January (1.26").
Average rainfall days in September
Riverside, IA
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is May (19.2 days).
The month with the least rainy days is February (4.8 days).
Average snowfall in September
Riverside, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.57").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Riverside, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.8 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
Riverside, IA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 9h and 18min
The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Riverside, IA
- Average sunshine days in September: 16 days
The month with the most sunshine days is November (18.2 days).
The month with the least sunshine days is June (9.3 days).
Average UV index in September
Riverside, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Riverside, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is August (Cloud cover 29).
Average visibility in September
Riverside, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
