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
Saint Charles's weather subtly changes with the onset of September, barely falling from 85.5°F (29.7°C) in August to a still warm 79.7°F (26.5°C). Throughout September, Saint Charles experiences a low-temperature average of 60.1°F (15.6°C).Humidity
In Saint Charles, the average relative humidity in September is 73%.Rainfall
In Saint Charles, in September, it is raining for 12.3 days, with typically 1.73" (44mm) of accumulated precipitation. Throughout the year, there are 141.9 rainfall days, and 27.68" (703mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In Saint Charles, the average length of the day in September is 12h and 26min.On the first day of September in Saint Charles, sunrise is at 6:31 am and sunset at 7:31 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 6:45 pm CDT.
Sunshine
In September, the average sunshine is 9.6h.UV index
The average daily maximum UV index in September in Saint Charles is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: In September, the maximum UV index of 5 suggests this advice:
Take precautions - Protection against sun damage is advised. The midday Sun can be harmful due to its potent UV radiation; seek shade and reduce exposure. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
What is the average length of the day in September?
When are sunrise and sunset in September?
How many hours of sunshine does Saint Charles have in September?
What is the UV index reading in September?
Average temperature in September
Saint Charles, MO
- Average high temperature in September: 79.7°F
The warmest month (with the highest average high temperature) is July (86.7°F).
The month with the lowest average high temperature is January (37.2°F).
- Average low temperature in September: 60.1°F
The month with the highest average low temperature is July (68.9°F).
The coldest month (with the lowest average low temperature) is January (24.3°F).
Average pressure in September
Saint Charles, 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
Saint Charles, MO
- Average wind speed in September: 6.1mph
The windiest month (with the highest average wind speed) is January (9.3mph).
The calmest months (with the lowest average wind speed) are July and August (5.6mph).
Average humidity in September
Saint Charles, MO
- Average humidity in September: 73%
The month with the highest relative humidity is May (77%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
Saint Charles, MO
- Average rainfall in September: 1.73"
The wettest month (with the highest rainfall) is May (3.31").
The driest month (with the least rainfall) is February (1.42").
Average rainfall days in September
Saint Charles, MO
- Average rainfall days in September: 12.3 days
The month with the highest number of rainy days is July (16.3 days).
The months with the least rainy days are February and December (7.3 days).
Average snowfall in September
Saint Charles, MO
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.05").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Saint Charles, MO
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (6.8 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
Saint Charles, 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 36min).
Average sunshine days in September
Saint Charles, MO
- Average sunshine days in September: 15.3 days
The month with the most sunshine days is October (19.2 days).
The month with the least sunshine days is July (11.4 days).
Average UV index in September
Saint Charles, MO
- Average UV index in September: 5
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).
Average cloud cover in September
Saint Charles, MO
- Average cloud cover in September: 28
The month with the most cloud cover is January (Cloud cover 50).
The month with the least cloud cover is August (Cloud cover 27).
Average visibility in September
Saint Charles, 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).
Saint Charles, Missouri, USA
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