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's arrival signals a moderate reduction in the average high-temperature, easing from a moderately hot 82°F (27.8°C) in August to a still warm 76.6°F (24.8°C). An average minimum temperature of 57.6°F (14.2°C) marks the month of September.Humidity
The average relative humidity in September is 75%.Rainfall
In Marietta, during September, the rain falls for 11 days and regularly aggregates up to 2.09" (53mm) of precipitation. Throughout the year, in Marietta, there are 131.7 rainfall days, and 22.48" (571mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 27min.On the first day of the month, sunrise is at 6:29 am and sunset at 7:33 pm. On the last day of September, sunrise is at 6:57 am and sunset at 6:44 pm CDT.
Sunshine
The average sunshine in September in Marietta, Illinois, is 9.3h.UV index
In September, the average daily maximum UV index in Marietta is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: A maximum daily UV index of 4 during September morphs into the following directions:
Guard yourself - An obligation to protect skin and eyes from harm exists. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in Marietta in September?
What is the average humidity in September in Marietta?
How much does it rain in Marietta in September?
When it does not snow in Marietta?
Does it snow in Marietta in September?
How many hours of daylight does Marietta have in September?
When are sunrise and sunset in September in Marietta?
How many hours of sunshine does Marietta have in September?
What is the UV index reading in September in Marietta?
Average temperature in September
Marietta, IL
- Average high temperature in September: 76.6°F
The warmest month (with the highest average high temperature) is July (82.8°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 (65.8°F).
The coldest month (with the lowest average low temperature) is January (19.4°F).
Average pressure in September
Marietta, IL
- 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 (29.91"Hg).
Average wind speed in September
Marietta, IL
- Average wind speed in September: 7.5mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.5mph).
Average humidity in September
Marietta, IL
- Average humidity in September: 75%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Marietta, IL
- Average rainfall in September: 2.09"
The wettest month (with the highest rainfall) is May (3.23").
The driest month (with the least rainfall) is December (0.94").
Average rainfall days in September
Marietta, IL
- Average rainfall days in September: 11 days
The month with the highest number of rainy days is May (16.7 days).
The month with the least rainy days is February (4.7 days).
Average snowfall in September
Marietta, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (3.35").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Marietta, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.4 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
Marietta, 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 18min).
- Average sunshine in September: 9h and 2min
The months with the most sunshine are June and July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Marietta, IL
- Average sunshine days in September: 17.1 days
The month with the most sunshine days is December (20.4 days).
The month with the least sunshine days is June (11.1 days).
Average UV index in September
Marietta, IL
- Average UV index in September: 4
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
Marietta, IL
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is September (Cloud cover 29).
Average visibility in September
Marietta, 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).
Marietta, Illinois, USA
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