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 brings an average high-temperature of a still warm 75.9°F (24.4°C), nearly identical to the preceding month. Dewey's nights in September experience an average temperature drop to a mild 57.6°F (14.2°C).Humidity
In September, the average relative humidity is 77%.Rainfall
In September, in Dewey, the rain falls for 9.1 days. Throughout September, 0.67" (17mm) of precipitation is accumulated. In Dewey, Illinois, during the entire year, the rain falls for 115.9 days and collects up to 10.87" (276mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
The average length of the day in September in Dewey is 12h and 27min.On the first day of the month, sunrise is at 6:21 am and sunset at 7:24 pm. On the last day of September, in Dewey, sunrise is at 6:49 am and sunset at 6:36 pm CDT.
Sunshine
In September, the average sunshine is 8.9h.UV index
The average daily maximum UV index in September in Dewey is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.Note: In September, the maximum UV index of 5 transforms into these recommendations:
Adopt protective measures - It is advised to guard against sun damage. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun.
Frequently asked questions
What is the usual temperature for Dewey in September?
What is the average humidity in September in Dewey?
How many days does it rain in September in Dewey?
When it does not snow in Dewey?
How many hours of daylight does Dewey have in September?
When is the sunrise / sunset in September in Dewey?
How long on average sun shines in September in Dewey?
How high is the UV index in September in Dewey?
Average temperature in September
Dewey, IL
- Average high temperature in September: 75.9°F
The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (31.5°F).
- Average low temperature in September: 57.6°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 (19.8°F).
Average pressure in September
Dewey, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Dewey, IL
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is January (10.9mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).
Average humidity in September
Dewey, IL
- Average humidity in September: 77%
The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Dewey, IL
- Average rainfall in September: 0.67"
The wettest month (with the highest rainfall) is May (1.46").
The driest month (with the least rainfall) is February (0.51").
Average rainfall days in September
Dewey, IL
- Average rainfall days in September: 9.1 days
The month with the highest number of rainy days is May (14.4 days).
The month with the least rainy days is January (4.5 days).
Average snowfall in September
Dewey, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (1.3").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Dewey, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Dewey, IL
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 8h and 5min
The month with the most sunshine is June (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Dewey, IL
- Average sunshine days in September: 17.5 days
The month with the most sunshine days is November (21.4 days).
The month with the least sunshine days is July (12.3 days).
Average UV index in September
Dewey, IL
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Dewey, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 31).
Average visibility in September
Dewey, 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).
Dewey, Illinois, USA
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