September weather forecastRiver Junction, IA
September
Weather in September
September, the first month of the autumn in River Junction, is also a moderately hot month, with an average temperature ranging between max 75.2°F (24°C) and min 55.8°F (13.2°C).Temperature
In River Junction, the average high-temperature in September slightly decreases from 80.6°F (27°C) in August to a still moderately hot 75.2°F (24°C). River Junction reports an average nighttime low-temperature of 55.8°F (13.2°C) in September.Humidity
In River Junction, the average relative humidity in September is 76%.Rainfall
In River Junction, Iowa, during September, the rain falls for 12 days and regularly aggregates up to 2.44" (62mm) of precipitation. In River Junction, during the entire year, the rain falls for 140.4 days and collects up to 29.57" (751mm) of precipitation.Snowfall
In River Junction, snow does not fall in May through September.Daylight
In River Junction, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:32 am and sunset at 7:38 pm. On the last day of September, sunrise is at 7:02 am and sunset at 6:48 pm CDT.
Sunshine
In River Junction, 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 medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.Note: A maximum UV index of 4 in September translates into the following recommendations:
Take heed. Individuals of lighter complexion can be burned in less than half an hour. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
River Junction, IA
- Average high temperature in September: 75.2°F
The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (27.3°F).
- Average low temperature in September: 55.8°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (15.3°F).
Average pressure in September
River Junction, 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 (29.9"Hg).
Average wind speed in September
River Junction, IA
- Average wind speed in September: 8mph
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 (6.9mph).
Average humidity in September
River Junction, IA
- Average humidity in September: 76%
The months with the highest relative humidity are January and July (83%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
River Junction, IA
- Average rainfall in September: 2.44"
The wettest month (with the highest rainfall) is May (4.69").
The driest months (with the least rainfall) are January and February (1.34").
Average rainfall days in September
River Junction, IA
- Average rainfall days in September: 12 days
The month with the highest number of rainy days is May (18.4 days).
The month with the least rainy days is February (5 days).
Average snowfall in September
River Junction, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (5.28").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
River Junction, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
River Junction, IA
- Average daylight in September: 12h and 30min
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 12min).
- Average sunshine in September: 9h and 18min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
River Junction, IA
- Average sunshine days in September: 17.1 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (10 days).
Average UV index in September
River Junction, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
River Junction, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 29).
Average visibility in September
River Junction, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
