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
With the arrival of September, Diagonal experiences a modest decline in average high-temperatures, transitioning from 81.7°F (27.6°C) in August to a still warm 75.9°F (24.4°C). Diagonal's nights in September experience an average temperature drop to a refreshing 56.3°F (13.5°C).Humidity
In September, the average relative humidity is 76%.Rainfall
In September, the rain falls for 11 days. Throughout September, 2.24" (57mm) of precipitation is accumulated. Throughout the year, there are 126.9 rainfall days, and 22.6" (574mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall in Diagonal, Iowa.Daylight
In Diagonal, the average length of the day in September 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 7:13 am and sunset at 7:00 pm CDT.
Sunshine
The average sunshine in September is 9.3h.UV index
In Diagonal, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: A maximum high UV index of 5 in September translates into the following recommendations:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Diagonal have in September?
When are sunrise and sunset in September?
How long on average sun shines in September in Diagonal?
What is the UV index reading in September?
Average temperature in September
Diagonal, IA
- Average high temperature in September: 75.9°F
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is January (30.6°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (16.9°F).
Average pressure in September
Diagonal, 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
Diagonal, IA
- Average wind speed in September: 7.8mph
The windiest months (with the highest average wind speed) are January, February and March (10.3mph).
The calmest months (with the lowest average wind speed) are July and August (6.8mph).
Average humidity in September
Diagonal, IA
- Average humidity in September: 76%
The month with the highest relative humidity is June (82%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Diagonal, IA
- Average rainfall in September: 2.24"
The wettest month (with the highest rainfall) is June (3.86").
The driest months (with the least rainfall) are February and December (0.71").
Average rainfall days in September
Diagonal, IA
- Average rainfall days in September: 11 days
The month with the highest number of rainy days is May (17.8 days).
The month with the least rainy days is January (4.1 days).
Average snowfall in September
Diagonal, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.54").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Diagonal, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Diagonal, IA
- Average daylight in September: 12h and 3min
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 2min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).
Average sunshine days in September
Diagonal, IA
- Average sunshine days in September: 16.9 days
The month with the most sunshine days is November (21.2 days).
The month with the least sunshine days is May (10.6 days).
Average UV index in September
Diagonal, IA
- Average UV index in September: 5
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
Diagonal, IA
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 50).
The month with the least cloud cover is July (Cloud cover 28).
Average visibility in September
Diagonal, 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).
Diagonal, Iowa, USA
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