September weather forecastClinton, IA
September
Weather in September
September encounters the beginning of the autumnal shift in Clinton. The high temperatures of summer gradually decline, with average highs reducing to 74.3°F (23.5°C). With the leaves commencing to change their hues, September ushers in the spellbinding pallet of fall colors. This shift in seasons reveals a new facet of Clinton's mesmerizing landscape.Temperature
The shift from August to September coincides with a small decrease in the average high-temperature, down to a still warm 74.3°F (23.5°C) from a moderately hot 79.9°F (26.6°C). An average low-temperature of 55°F (12.8°C) is recorded in the month of September.Humidity
In Clinton, the average relative humidity in September is 77%.Rainfall
In Clinton, in September, it is raining for 9.9 days, with typically 1.54" (39mm) of accumulated precipitation. In Clinton, during the entire year, the rain falls for 126.2 days and collects up to 19.37" (492mm) of precipitation.Snowfall
May through September are months without snowfall.Daylight
In Clinton, Iowa, the average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:27 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:43 pm CDT.
Sunshine
In September, the average sunshine in Clinton is 9.2h.UV index
In September, the average daily maximum UV index in Clinton is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: In September, a daily UV index of 4 turns into the following recommendations:
Exercise caution. Those with pale skin may experience burns in less than half an hour. To avoid the Sun's strongest rays, limit exposure around the mid-day period. 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
Clinton, IA
- Average high temperature in September: 74.3°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (26.8°F).
- Average low temperature in September: 55°F
The month with the highest average low temperature is July (63.9°F).
The coldest month (with the lowest average low temperature) is January (14.5°F).
Average pressure in September
Clinton, IA
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Clinton, IA
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Clinton, IA
- Average humidity in September: 77%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Clinton, IA
- Average rainfall in September: 1.54"
The wettest month (with the highest rainfall) is May (3.19").
The driest months (with the least rainfall) are January and February (0.79").
Average rainfall days in September
Clinton, IA
- Average rainfall days in September: 9.9 days
The month with the highest number of rainy days is May (16.9 days).
The month with the least rainy days is January (4.3 days).
Average snowfall in September
Clinton, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.8").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Clinton, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.3 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
Clinton, 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 12min).
- Average sunshine in September: 9h and 12min
The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in September
Clinton, IA
- Average sunshine days in September: 18.3 days
The month with the most sunshine days is November (19.3 days).
The month with the least sunshine days is May (11.8 days).
Average UV index in September
Clinton, IA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Clinton, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 59).
The month with the least cloud cover is September (Cloud cover 30).
Average visibility in September
Clinton, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
