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
Union experiences a subtle adjustment in high-temperatures to a still warm 73.8°F (23.2°C) with the onset of September, maintaining near parity with August's 78.4°F (25.8°C). During September, Union experiences a consistent low-temperature average of 54.5°F (12.5°C).Humidity
In Union, the average relative humidity in September is 77%.Rainfall
In Union, in September, it is raining for 8.1 days, with typically 0.51" (13mm) of accumulated precipitation. Throughout the year, there are 83.5 rainfall days, and 6.5" (165mm) of precipitation is accumulated.Snowfall
In Union, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:38 am and sunset at 7:45 pm. On the last day of September, sunrise is at 7:09 am and sunset at 6:54 pm CDT.
Sunshine
The average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the average person.Note: A maximum high UV index of 4 in September translates into the following recommendations:
Take necessary precautions - Protection from skin and eye injury is mandatory. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Union in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
What time are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Union, IA
- Average high temperature in September: 73.8°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (24.4°F).
- Average low temperature in September: 54.5°F
The month with the highest average low temperature is July (63.9°F).
The coldest month (with the lowest average low temperature) is January (12.2°F).
Average pressure in September
Union, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Union, IA
- Average wind speed in September: 8.4mph
The windiest month (with the highest average wind speed) is April (10.9mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).
Average humidity in September
Union, IA
- Average humidity in September: 77%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Union, IA
- Average rainfall in September: 0.51"
The wettest month (with the highest rainfall) is May (1.06").
The driest months (with the least rainfall) are January and February (0.24").
Average rainfall days in September
Union, IA
- Average rainfall days in September: 8.1 days
The month with the highest number of rainy days is May (11.6 days).
The months with the least rainy days are January and February (2 days).
Average snowfall in September
Union, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.79").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Union, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (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
Union, IA
- Average daylight in September: 12h and 3min
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: 9h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in September
Union, IA
- Average sunshine days in September: 20.3 days
The month with the most sunshine days is January (25.2 days).
The month with the least sunshine days is June (15.8 days).
Average UV index in September
Union, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in September
Union, IA
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is September (Cloud cover 31).
Average visibility in September
Union, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
Union, Iowa, USA
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