September weather forecastOnawa, IA
September
Weather in September
The first month of the autumn, September, is still a warm month in Onawa, Iowa, with temperature in the range of an average high of 76.1°F (24.5°C) and an average low of 56.3°F (13.5°C).Temperature
Onawa observes a small decrease in the average high-temperature with the arrival of September, falling from August's warm 82°F (27.8°C) to a still moderately hot 76.1°F (24.5°C). September nights observe an average temperature dip to a mild 56.3°F (13.5°C).Humidity
In September, the average relative humidity in Onawa is 71%.Rainfall
In Onawa, in September, it is raining for 11.3 days, with typically 2.05" (52mm) of accumulated precipitation. Throughout the year, in Onawa, there are 117.6 rainfall days, and 21.89" (556mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:50 am and sunset at 7:57 pm. On the last day of September, in Onawa, sunrise is at 7:21 am and sunset at 7:07 pm CDT.
Sunshine
The average sunshine in September in Onawa is 8.9h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.Note: In September, the maximum UV index of 4 transforms into these recommendations:
Undertake precautions - It is suggested to shield oneself from sunburn. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Onawa, IA
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (28°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (15.1°F).
Average pressure in September
Onawa, IA
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in September
Onawa, IA
- Average wind speed in September: 8.8mph
The windiest month (with the highest average wind speed) is April (10.9mph).
The calmest month (with the lowest average wind speed) is July (7.4mph).
Average humidity in September
Onawa, IA
- Average humidity in September: 71%
The month with the highest relative humidity is January (82%).
The months with the lowest relative humidity are April and October (66%).
Average rainfall in September
Onawa, IA
- Average rainfall in September: 2.05"
The wettest month (with the highest rainfall) is May (3.31").
The driest month (with the least rainfall) is January (0.67").
Average rainfall days in September
Onawa, IA
- Average rainfall days in September: 11.3 days
The month with the highest number of rainy days is May (16.6 days).
The month with the least rainy days is February (2.7 days).
Average snowfall in September
Onawa, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.03").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Onawa, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.9 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Onawa, 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: 8h and 54min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in September
Onawa, IA
- Average sunshine days in September: 16.4 days
The month with the most sunshine days is November (21.5 days).
The month with the least sunshine days is June (12 days).
Average UV index in September
Onawa, IA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are February and December (UV index 1).
Average cloud cover in September
Onawa, IA
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is July (Cloud cover 26).
Average visibility in September
Onawa, 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).
