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
September's arrival coincides with a soft drop in the average high-temperature, subtly decreasing from August's moderately hot 77.2°F (25.1°C) to an agreeable 70.7°F (21.5°C). Throughout September, Decorah records an average temperature of 52°F (11.1°C) at night.Humidity
In Decorah, the average relative humidity in September is 80%.Rainfall
In Decorah, in September, it is raining for 13.3 days, with typically 2.48" (63mm) of accumulated precipitation. In Decorah, during the entire year, the rain falls for 149 days and collects up to 30.59" (777mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In Decorah, the average length of the day in September 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, sunrise is at 7:04 am and sunset at 6:49 pm CDT.
Sunshine
In Decorah, the average sunshine in September is 8.9h.UV index
In Decorah, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for the average person.Note: The daily high UV index of 4 during September translates into the following recommendations:
Ensure safety - Recommendations to avert sunburn are presented. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage.
Frequently asked questions
What is the temperature in September in Decorah?
What is the average humidity in September in Decorah?
How much does it rain in Decorah in September?
When it does not snow in Decorah?
Does it snow in Decorah in September?
What is the average length of the day in September in Decorah?
What time are sunrise and sunset in September in Decorah?
How many hours of sunshine does Decorah have in September?
What is the UV index reading in September in Decorah?
Average temperature in September
Decorah, IA
- Average high temperature in September: 70.7°F
The warmest month (with the highest average high temperature) is July (78.4°F).
The month with the lowest average high temperature is January (22.3°F).
- Average low temperature in September: 52°F
The month with the highest average low temperature is July (61.9°F).
The coldest month (with the lowest average low temperature) is January (9.7°F).
Average pressure in September
Decorah, IA
- Average pressure in September: 30.02"Hg
The months with the highest atmospheric pressure are January and February (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Decorah, IA
- Average wind speed in September: 8.1mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in September
Decorah, IA
- Average humidity in September: 80%
The months with the highest relative humidity are January and February (89%).
The month with the lowest relative humidity is October (76%).
Average rainfall in September
Decorah, IA
- Average rainfall in September: 2.48"
The wettest month (with the highest rainfall) is June (5.04").
The driest month (with the least rainfall) is January (1.1").
Average rainfall days in September
Decorah, IA
- Average rainfall days in September: 13.3 days
The months with the highest number of rainy days are May and June (20.3 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in September
Decorah, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.98").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Decorah, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (14.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Decorah, 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 0min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in September
Decorah, IA
- Average sunshine days in September: 14.5 days
The month with the most sunshine days is November (16.2 days).
The month with the least sunshine days is June (7.1 days).
Average UV index in September
Decorah, IA
- Average UV index in September: 4
The months with the highest UV index are May, June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
Decorah, IA
- Average cloud cover in September: 33
The month with the most cloud cover is January (Cloud cover 64).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Decorah, IA
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, August, September, October and November (6mi).
The months with the lowest visibility are January, February, July and December (5mi).
Decorah, Iowa, USA
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