September weather forecastCromwell, IA
September
Weather in September
September, the first month of the autumn in Cromwell, is still a warm month, with an average temperature ranging between max 75°F (23.9°C) and min 56.1°F (13.4°C).Temperature
September brings a minor shift in the average high-temperature, adjusting from a warm 81°F (27.2°C) in August to a still moderately hot 75°F (23.9°C). During September, Cromwell records an average temperature of 56.1°F (13.4°C) at night.Humidity
In Cromwell, the average relative humidity in September is 77%.Rainfall
In September, the rain falls for 11.6 days. Throughout September, 2.2" (56mm) of precipitation is accumulated. In Cromwell, during the entire year, the rain falls for 127.7 days and collects up to 23.39" (594mm) of precipitation.Snowfall
In Cromwell, Iowa, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 27min.On the first day of the month, sunrise is at 6:45 am and sunset at 7:49 pm. On the last day of September, sunrise is at 7:14 am and sunset at 7:00 pm CDT.
Sunshine
In September, the average sunshine is 9.2h.UV index
In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for the ordinary person.Note: In September, an average UV index of 4 transforms into the following instructions:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Cromwell, IA
- Average high temperature in September: 75°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (29.1°F).
- Average low temperature in September: 56.1°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (15.8°F).
Average pressure in September
Cromwell, 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
Cromwell, IA
- Average wind speed in September: 8.2mph
The windiest months (with the highest average wind speed) are January and February (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).
Average humidity in September
Cromwell, IA
- Average humidity in September: 77%
The months with the highest relative humidity are January and June (82%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Cromwell, IA
- Average rainfall in September: 2.2"
The wettest month (with the highest rainfall) is June (4.17").
The driest month (with the least rainfall) is January (0.75").
Average rainfall days in September
Cromwell, IA
- Average rainfall days in September: 11.6 days
The month with the highest number of rainy days is May (17.4 days).
The month with the least rainy days is January (3.7 days).
Average snowfall in September
Cromwell, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.15").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Cromwell, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Cromwell, 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 18min).
- Average sunshine in September: 9h and 12min
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 24min).
Average sunshine days in September
Cromwell, IA
- Average sunshine days in September: 16.3 days
The month with the most sunshine days is November (20.2 days).
The month with the least sunshine days is May (10.7 days).
Average UV index in September
Cromwell, IA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Cromwell, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are July and September (Cloud cover 30).
Average visibility in September
Cromwell, IA
- 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).





