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 in O'Fallon, Missouri, coincides with a soft drop in the average high-temperature, subtly decreasing from August's warm 85.5°F (29.7°C) to a still moderately hot 79.5°F (26.4°C). In the month of September, O'Fallon's average low-temperature falls to a refreshing 60.1°F (15.6°C).Humidity
In O'Fallon, the average relative humidity in September is 73%.Rainfall
In September, in O'Fallon, the rain falls for 11.3 days. Throughout September, 1.42" (36mm) of precipitation is accumulated. Throughout the year, there are 132.3 rainfall days, and 21.06" (535mm) of precipitation is accumulated.Snowfall
In O'Fallon, snow does not fall in April through October.Daylight
In O'Fallon, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 6:32 am and sunset at 7:32 pm. On the last day of September, sunrise is at 6:58 am and sunset at 6:46 pm CDT.
Sunshine
The average sunshine in September in O'Fallon is 9.5h.UV index
In O'Fallon, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: In September, the UV index of 5 transforms into the following advice:
Heed the precautions - It is counselled to guard against solar damage. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses.
Frequently asked questions
What is the usual temperature for O'Fallon in September?
What is the average humidity in September in O'Fallon?
How much does it rain in O'Fallon in September?
When it does not snow in O'Fallon?
What is the average length of the day in September in O'Fallon?
When is the sunrise / sunset in September in O'Fallon?
How many hours of sunshine does O'Fallon have in September?
What is the UV index intensity in September in O'Fallon?
Average temperature in September
O'Fallon, MO
- Average high temperature in September: 79.5°F
The warmest month (with the highest average high temperature) is July (87.1°F).
The month with the lowest average high temperature is January (37.4°F).
- Average low temperature in September: 60.1°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 (23.7°F).
Average pressure in September
O'Fallon, 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
O'Fallon, MO
- Average wind speed in September: 6.1mph
The windiest month (with the highest average wind speed) is January (9.1mph).
The calmest month (with the lowest average wind speed) is July (5.5mph).
Average humidity in September
O'Fallon, MO
- Average humidity in September: 73%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (70%).
Average rainfall in September
O'Fallon, MO
- Average rainfall in September: 1.42"
The wettest month (with the highest rainfall) is May (2.76").
The driest month (with the least rainfall) is December (0.91").
Average rainfall days in September
O'Fallon, MO
- Average rainfall days in September: 11.3 days
The month with the highest number of rainy days is May (15.7 days).
The month with the least rainy days is February (6.8 days).
Average snowfall in September
O'Fallon, MO
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.61").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
O'Fallon, MO
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (5.8 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
O'Fallon, 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 3min
The month with the most sunshine is June (Average sunshine: 10h and 30min).
The months with the least sunshine are January and February (Average sunshine: 4h and 42min).
Average sunshine days in September
O'Fallon, MO
- Average sunshine days in September: 16.7 days
The month with the most sunshine days is December (20.6 days).
The month with the least sunshine days is July (12.6 days).
Average UV index in September
O'Fallon, 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, November and December (UV index 2).
Average cloud cover in September
O'Fallon, MO
- Average cloud cover in September: 28
The month with the most cloud cover is January (Cloud cover 50).
The months with the least cloud cover are June, July, August and September (Cloud cover 28).
Average visibility in September
O'Fallon, 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).
O'Fallon, Missouri, USA
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