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
During the shift to September, a minor reduction in average high-temperature is observed, shifting from a moderately hot 79.3°F (26.3°C) in August to a still warm 73.9°F (23.3°C). Nighttime temperature in Rock Falls dips to a mean of 55.2°F (12.9°C) during September.Humidity
In September, the average relative humidity is 78%.Rainfall
In Rock Falls, in September, it is raining for 9.7 days, with typically 1.26" (32mm) of accumulated precipitation. In Rock Falls, Illinois, during the entire year, the rain falls for 130.2 days and collects up to 17.36" (441mm) of precipitation.Snowfall
In Rock Falls, snow does not fall in May through September.Daylight
In Rock Falls, Illinois, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:25 am and sunset at 7:31 pm. On the last day of September, in Rock Falls, sunrise is at 6:55 am and sunset at 6:41 pm CDT.
Sunshine
The average sunshine in September is 9.1h.UV index
In Rock Falls, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for average individuals.Note: During September, 4 as the daily maximum UV index converts into the following advice:
Undertake precautions - It is suggested to shield oneself from sunburn. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Frequently asked questions
What is the average September temperature in Rock Falls?
What is the average humidity in September in Rock Falls?
How many days does it rain in September in Rock Falls?
When it does not snow in Rock Falls?
Does it snow in Rock Falls in September?
How many hours of daylight does Rock Falls have in September?
What time are sunrise and sunset in September in Rock Falls?
How many hours of sunshine does Rock Falls have in September?
How high is the UV index in September in Rock Falls?
Average temperature in September
Rock Falls, IL
- Average high temperature in September: 73.9°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is January (27.7°F).
- Average low temperature in September: 55.2°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 (14.9°F).
Average pressure in September
Rock Falls, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Rock Falls, IL
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).
Average humidity in September
Rock Falls, IL
- Average humidity in September: 78%
The months with the highest relative humidity are January and July (85%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Rock Falls, IL
- Average rainfall in September: 1.26"
The wettest month (with the highest rainfall) is May (2.83").
The driest months (with the least rainfall) are January and February (0.75").
Average rainfall days in September
Rock Falls, IL
- Average rainfall days in September: 9.7 days
The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is January (4.8 days).
Average snowfall in September
Rock Falls, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.56").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Rock Falls, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.2 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
Rock Falls, IL
- 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 1min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in September
Rock Falls, IL
- Average sunshine days in September: 18.4 days
The months with the most sunshine days are November and December (18.8 days).
The month with the least sunshine days is June (11.3 days).
Average UV index in September
Rock Falls, IL
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Rock Falls, IL
- Average cloud cover in September: 31
The month with the most cloud cover is January (Cloud cover 60).
The month with the least cloud cover is September (Cloud cover 31).
Average visibility in September
Rock Falls, IL
- 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).
Rock Falls, Illinois, USA
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