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
In September, the meteorological conditions change slightly, with the average high-temperature moving from a warm 77.5°F (25.3°C) in August to a pleasant 71.6°F (22°C). Donnan reports an average low-temperature of 52.9°F (11.6°C) during the nights of September.Humidity
In September, the average relative humidity is 80%.Rainfall
In Donnan, Iowa, in September, during 12 rainfall days, 2.32" (59mm) of precipitation is typically accumulated. Throughout the year, in Donnan, Iowa, there are 140.2 rainfall days, and 28.7" (729mm) of precipitation is accumulated.Snowfall
In Donnan, snow does not fall in June through September.Daylight
In September, the average length of the day in Donnan is 12h and 29min.On the first day of the month, sunrise is at 6:32 am and sunset at 7:41 pm. On the last day of September, in Donnan, sunrise is at 7:04 am and sunset at 6:49 pm CDT.
Sunshine
The average sunshine in September is 9h.UV index
In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum daily UV index, 4 in September, converts into the following recommendations:
Guard yourself - An obligation to protect skin and eyes from harm exists. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Enhance your sun protection with tightly woven, yet airy clothing.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature in Donnan?
What is the average humidity in September in Donnan?
How much does it rain in Donnan in September?
When it does not snow in Donnan?
Does it snow in Donnan in September?
How many hours of daylight does Donnan have in September?
What time are sunrise and sunset in September in Donnan?
How long on average sun shines in September in Donnan?
How high is the UV index in September in Donnan?
Average temperature in September
Donnan, IA
- Average high temperature in September: 71.6°F
The warmest month (with the highest average high temperature) is July (79°F).
The month with the lowest average high temperature is January (23.7°F).
- Average low temperature in September: 52.9°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (10.9°F).
Average pressure in September
Donnan, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Donnan, IA
- Average wind speed in September: 8.2mph
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
Donnan, IA
- Average humidity in September: 80%
The months with the highest relative humidity are January and February (88%).
The month with the lowest relative humidity is October (74%).
Average rainfall in September
Donnan, IA
- Average rainfall in September: 2.32"
The wettest month (with the highest rainfall) is June (4.45").
The driest month (with the least rainfall) is January (1.06").
Average rainfall days in September
Donnan, IA
- Average rainfall days in September: 12 days
The month with the highest number of rainy days is May (18.9 days).
The month with the least rainy days is February (3.3 days).
Average snowfall in September
Donnan, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.59").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Donnan, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Donnan, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 9h and 0min
The months with the most sunshine are July and August (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in September
Donnan, IA
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is November (18 days).
The month with the least sunshine days is June (8.9 days).
Average UV index in September
Donnan, IA
- Average UV index in September: 4
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, November and December (UV index 1).
Average cloud cover in September
Donnan, IA
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in September
Donnan, IA
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February and July (5mi).
Donnan, Iowa, USA
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