Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
Cooper in September witnesses an average high-temperature of a still warm 74.8°F (23.8°C), indicating a slight variation from August's 80.1°F (26.7°C). An average low-temperature of 55.8°F (13.2°C) is observed during September nights.Humidity
The average relative humidity in September is 75%.Rainfall
In Cooper, in September, during 11.2 rainfall days, 2.91" (74mm) of precipitation is typically accumulated. Throughout the year, there are 125.7 rainfall days, and 26.5" (673mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
In Cooper, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:43 am and sunset at 7:50 pm. On the last day of September, sunrise is at 7:14 am and sunset at 7:00 pm CDT.
Sunshine
The average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.Note: During September, 4 as the daily maximum UV index converts into the following advice:
Guard yourself - Avoiding sunburn is suggested. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Stay sun-safe with clothing that is both closely woven and worn loosely.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
When are sunrise and sunset in September?
How many hours of sunshine does Cooper have in September?
What is the UV index reading in September?
Average temperature in September
Cooper, IA
- Average high temperature in September: 74.8°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (26.8°F).
- Average low temperature in September: 55.8°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).
Average pressure in September
Cooper, IA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Cooper, IA
- Average wind speed in September: 8.3mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).
Average humidity in September
Cooper, IA
- Average humidity in September: 75%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (69%).
Average rainfall in September
Cooper, IA
- Average rainfall in September: 2.91"
The wettest month (with the highest rainfall) is May (4.06").
The driest month (with the least rainfall) is January (0.87").
Average rainfall days in September
Cooper, IA
- Average rainfall days in September: 11.2 days
The month with the highest number of rainy days is June (17.3 days).
The month with the least rainy days is February (3.4 days).
Average snowfall in September
Cooper, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.29").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Cooper, 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 June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Cooper, IA
- Average daylight in September: 12h and 3min
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 2min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
Cooper, IA
- Average sunshine days in September: 17.2 days
The month with the most sunshine days is November (19.4 days).
The month with the least sunshine days is June (11.1 days).
Average UV index in September
Cooper, 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, February, October, November and December (UV index 2).
Average cloud cover in September
Cooper, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and September (Cloud cover 30).
Average visibility in September
Cooper, IA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Cooper, Iowa, USA
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