Contents
- Weather in September
- Frequently asked questions
- Average temperature 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 UV index in September
Weather in September
Temperature
The advent of September in St. Louis brings a subtle shift in temperature, with the average high moving from a hot 88°F in August to a warm 80.2°F. During the month of September, St. Louis experiences a steady low-temperature average of 60.6°F.Humidity
The average relative humidity in September in St. Louis, Missouri, is 71.6%.Rainfall
In St. Louis, in September, during 7.4 rainfall days, 3.15" of precipitation is typically accumulated. Throughout the year, in St. Louis, Missouri, there are 112.6 rainfall days, and 40.94" of precipitation is accumulated.Snowfall
May through October are months without snowfall in St. Louis.Daylight
The average length of the day in September in St. Louis is 12h and 25min.On the first day of September in St. Louis, sunrise is at 6:30 am and sunset at 7:31 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:45 pm CDT.
Sunshine
In St. Louis, Missouri, the average sunshine in September is 7.9h.UV index
In September, the average daily maximum UV index in St. Louis is 7. A UV Index reading of 6 to 7 represents a high health hazard from unsafe exposure to UV radiation for ordinary individuals.Note: In September, the maximum UV index of 7 suggests these recommendations:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. Stay in the shade and limit sun exposure from 10 a.m. to 4 p.m., when UV radiation is most potent. Keep in mind that shade structures like parasols or canopies do not offer full protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
FAQ
What is the average September temperature in St. Louis?
What is the average humidity in September in St. Louis?
How many days does it rain in September in St. Louis?
When it does not snow in St. Louis?
How many hours of daylight does St. Louis have in September?
When are sunrise and sunset in September in St. Louis?
How long on average sun shines in September in St. Louis?
What is the UV index reading in September in St. Louis?
Average temperature in September
St. Louis, MO
- Average high temperature in September: 80.2°F
The warmest month (with the highest average high temperature) is July (89.1°F).
The month with the lowest average high temperature is January (39.9°F).
- Average low temperature in September: 60.6°F
The month with the highest average low temperature is July (71°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).
Average humidity in September
St. Louis, MO
- Average humidity in September: 71.6%
The month with the highest relative humidity is December (75.8%).
The month with the lowest relative humidity is April (63.5%).
Average rainfall in September
St. Louis, MO
- Average rainfall in September: 3.1"
The wettest month (with the highest rainfall) is May (4.7").
The driest month (with the least rainfall) is February (2.2").
Average rainfall days in September
St. Louis, MO
- Average rainfall days in September: 7.4 days
The month with the highest number of rainy days is May (11.9 days).
The month with the least rainy days is September (7.4 days).
Average snowfall in September
St. Louis, MO
- Average snowfall in September: 0"
The month with the highest snowfall is January (5.6").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
St. Louis, MO
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (4.7 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
St. Louis, 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: 7h and 5min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is December (Average sunshine: 4h and 12min).
Average UV index in September
St. Louis, MO
- Average UV index in September: 7
The months with the highest UV index are June, July and August (UV index 9).
The months with the lowest UV index are January and December (UV index 2).
St. Louis, Missouri, USA
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