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 marks a gentle change in average high-temperature, declining from August's warm 80.8°F (27.1°C) to a still moderately hot 75.4°F (24.1°C). Rock Island throughout September, records an average low-temperature of 56.3°F (13.5°C).Humidity
The average relative humidity in September in Rock Island, Illinois, is 76%.Rainfall
In Rock Island, Illinois, during September, the rain falls for 11.5 days and regularly aggregates up to 2.05" (52mm) of precipitation. Throughout the year, there are 138.1 rainfall days, and 27.32" (694mm) of precipitation is accumulated.Snowfall
In Rock Island, snow does not fall in May through September.Daylight
The average length of the day in September in Rock Island is 12h and 28min.On the first day of September in Rock Island, sunrise is at 6:29 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:45 pm CDT.
Sunshine
The average sunshine in September in Rock Island is 9.2h.UV index
In September, the average daily maximum UV index in Rock Island is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard 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 precautions - Protection against sun damage is advised. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Frequently asked questions
What are September temperatures in Rock Island?
What is the average humidity in September in Rock Island?
How much does it rain in Rock Island in September?
When it does not snow in Rock Island?
Does it snow in Rock Island in September?
How many hours of daylight does Rock Island have in September?
What time are sunrise and sunset in September in Rock Island?
How long on average sun shines in September in Rock Island?
What is the UV index intensity in September in Rock Island?
Average temperature in September
Rock Island, IL
- Average high temperature in September: 75.4°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (28°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (15.6°F).
Average pressure in September
Rock Island, IL
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Rock Island, IL
- Average wind speed in September: 7.8mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.7mph).
Average humidity in September
Rock Island, IL
- 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 (71%).
Average rainfall in September
Rock Island, IL
- Average rainfall in September: 2.05"
The wettest month (with the highest rainfall) is May (4.49").
The driest month (with the least rainfall) is February (1.1").
Average rainfall days in September
Rock Island, IL
- Average rainfall days in September: 11.5 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (4.3 days).
Average snowfall in September
Rock Island, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.98").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Rock Island, IL
- 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
Rock Island, IL
- 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 12min).
- Average sunshine in September: 9h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in September
Rock Island, IL
- Average sunshine days in September: 17.4 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (11.4 days).
Average UV index in September
Rock Island, IL
- Average UV index in September: 4
The months with the highest UV index are July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Rock Island, IL
- 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 August (Cloud cover 30).
Average visibility in September
Rock Island, IL
- 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).
Rock Island, Illinois, USA
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