September weather forecastRiley, KS
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Riley, Kansas, with an average temperature fluctuating between 60.4°F (15.8°C) and 79.7°F (26.5°C).Temperature
The advent of September brings a slight shift in average high-temperature, moving from a hot 87.4°F (30.8°C) in August to a warm 79.7°F (26.5°C). During September, the average low-temperature is a moderate 60.4°F (15.8°C).Humidity
In September, the average relative humidity in Riley is 68%.Rainfall
In September, the rain falls for 11.5 days. Throughout September, 1.65" (42mm) of precipitation is accumulated. In Riley, during the entire year, the rain falls for 114.8 days and collects up to 21.1" (536mm) of precipitation.Snowfall
In Riley, snow does not fall in May through September.Daylight
In Riley, the average length of the day in September is 12h and 26min.On the first day of September, sunrise is at 6:56 am and sunset at 7:57 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:10 pm CDT.
Sunshine
In September, the average sunshine in Riley is 8.9h.UV index
In September, the average daily maximum UV index in Riley is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum daily UV index of 5 during September translates into the following directions:
Exercise caution. The susceptibility of light skin individuals to burns is less than 30 minutes. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Riley, KS
- Average high temperature in September: 79.7°F
The warmest month (with the highest average high temperature) is July (89.6°F).
The month with the lowest average high temperature is January (38.8°F).
- Average low temperature in September: 60.4°F
The month with the highest average low temperature is July (69.8°F).
The coldest month (with the lowest average low temperature) is January (23°F).
Average pressure in September
Riley, KS
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in September
Riley, KS
- Average wind speed in September: 9.6mph
The windiest month (with the highest average wind speed) is April (11.8mph).
The calmest month (with the lowest average wind speed) is August (8.6mph).
Average humidity in September
Riley, KS
- Average humidity in September: 68%
The month with the highest relative humidity is May (74%).
The month with the lowest relative humidity is October (64%).
Average rainfall in September
Riley, KS
- Average rainfall in September: 1.65"
The wettest month (with the highest rainfall) is May (3.98").
The driest month (with the least rainfall) is January (0.63").
Average rainfall days in September
Riley, KS
- Average rainfall days in September: 11.5 days
The month with the highest number of rainy days is May (14.3 days).
The month with the least rainy days is January (3.7 days).
Average snowfall in September
Riley, KS
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.24").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Riley, KS
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.8 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
Riley, KS
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 8h and 54min
The months with the most sunshine are June and July (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).
Average sunshine days in September
Riley, KS
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is January (23.5 days).
The month with the least sunshine days is May (13.8 days).
Average UV index in September
Riley, KS
- Average UV index in September: 5
The month with the highest UV index is June (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Riley, KS
- Average cloud cover in September: 26
The month with the most cloud cover is March (Cloud cover 41).
The month with the least cloud cover is June (Cloud cover 22).
Average visibility in September
Riley, KS
- 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).





