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
As August makes way for September, Chesterfield's average high-temperature eases from a tropical 86.2°F (30.1°C) to a moderately hot 79.7°F (26.5°C). Chesterfield observes an average nighttime low-temperature of 59.9°F (15.5°C) during the month of September.Humidity
The average relative humidity in September is 73%.Rainfall
In Chesterfield, in September, during 12 rainfall days, 1.89" (48mm) of precipitation is typically accumulated. Throughout the year, there are 139.6 rainfall days, and 26.1" (663mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In Chesterfield, the average length of the day in September is 12h and 25min.On the first day of September, sunrise is at 6:32 am and sunset at 7:31 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:46 pm CDT.
Sunshine
In September, the average sunshine is 9.6h.UV index
In September, the average daily maximum UV index is 5. 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: The daily high UV index of 5 during September translates into the following recommendations:
Ensure safety - Sun damage prevention is strongly urged. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
How many hours of daylight does Chesterfield have in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Chesterfield have in September?
What is the UV index intensity in September?
Average temperature in September
Chesterfield, MO
- Average high temperature in September: 79.7°F
The warmest month (with the highest average high temperature) is July (87.4°F).
The month with the lowest average high temperature is January (37.8°F).
- Average low temperature in September: 59.9°F
The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (24.1°F).
Average pressure in September
Chesterfield, MO
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Chesterfield, MO
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is January (8.9mph).
The calmest month (with the lowest average wind speed) is July (5.4mph).
Average humidity in September
Chesterfield, MO
- Average humidity in September: 73%
The month with the highest relative humidity is May (78%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Chesterfield, MO
- Average rainfall in September: 1.89"
The wettest month (with the highest rainfall) is May (3.19").
The driest month (with the least rainfall) is February (1.3").
Average rainfall days in September
Chesterfield, MO
- Average rainfall days in September: 12 days
The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is January (6.8 days).
Average snowfall in September
Chesterfield, MO
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.69").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Chesterfield, MO
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6.7 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
Chesterfield, MO
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 9h and 4min
The month with the most sunshine is July (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).
Average sunshine days in September
Chesterfield, MO
- Average sunshine days in September: 16.5 days
The months with the most sunshine days are January and December (20.2 days).
The month with the least sunshine days is June (12 days).
Average UV index in September
Chesterfield, MO
- Average UV index in September: 5
The month with the highest UV index is June (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Chesterfield, MO
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 49).
The months with the least cloud cover are July and August (Cloud cover 27).
Average visibility in September
Chesterfield, MO
- 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).
Chesterfield, Missouri, USA
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