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
St. Louis observes a small decrease in the average high-temperature with the arrival of September, falling from August's tropical 88°F (31.1°C) to a moderately hot 80.2°F (26.8°C). Throughout September, St. Louis witnesses a consistent average low-temperature of 60.6°F (15.9°C).Humidity
In September, the average relative humidity in St. Louis is 71.6%.Rainfall
In St. Louis, during September, the rain falls for 7.4 days and regularly aggregates up to 3.15" (80mm) of precipitation. In St. Louis, during the entire year, the rain falls for 112.6 days and collects up to 40.94" (1040mm) of precipitation.Snowfall
May through October are months without snowfall in St. Louis.Daylight
The average length of the day in September in St. Louis, Missouri, is 12h and 25min.On the first day of the month, sunrise is at 6:30 am and sunset at 7:30 pm. On the last day of September, in St. Louis, Missouri, sunrise is at 6:56 am and sunset at 6:44 pm CDT.
Sunshine
In St. Louis, Missouri, the average sunshine in September is 7.9h.UV index
The average daily maximum UV index in September in St. Louis is 7. A UV Index estimate of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV radiation for ordinary individuals.Note: The UV index of 7 during September leads to these advisories:
Eschew overexposure. Those with light skin may suffer burns in fewer than 20 minutes. Limit your direct sun exposure, especially between 10 a.m. and 4 p.m., when UV radiation is strongest. Shade structures might not provide complete sun protection. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Frequently asked questions
What is the temperature in September in St. Louis?
What is the average humidity in September in St. Louis?
How much does it rain in St. Louis in September?
When it does not snow in St. Louis?
How many hours of daylight does St. Louis have in September?
When is the sunrise / sunset in September in St. Louis?
How long on average sun shines in September in St. Louis?
What is the UV index intensity 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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