September weather forecastLake Saint Louis, MO
September
Weather in September
September, the first month of the autumn in Lake Saint Louis, is also a moderately hot month, with an average temperature varying between 79.3°F (26.3°C) and 59.5°F (15.3°C).Temperature
With the onset of September, Lake Saint Louis's average high-temperature slightly adjusts, moderately receding from August's 85.5°F (29.7°C) to a still moderately hot 79.3°F (26.3°C). Lake Saint Louis's nighttime temperature during September is consistently averaged at a mild 59.5°F (15.3°C).Humidity
The average relative humidity in September is 74%.Rainfall
In September, in Lake Saint Louis, the rain falls for 11.9 days. Throughout September, 2.13" (54mm) of precipitation is accumulated. In Lake Saint Louis, during the entire year, the rain falls for 152.1 days and collects up to 32.01" (813mm) of precipitation.Snowfall
May through October are months without snowfall in Lake Saint Louis.Daylight
In Lake Saint Louis, 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, in Lake Saint Louis, sunrise is at 6:58 am and sunset at 6:46 pm CDT.
Sunshine
In September, the average sunshine is 9.6h.UV index
In Lake Saint Louis, Missouri, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for average individuals.Note: The UV index of 5 in September translates into these instructions:
Act with care - The suggestion to avoid sunburn is emphasized. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Lake Saint Louis, MO
- Average high temperature in September: 79.3°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: 59.5°F
The month with the highest average low temperature is July (68°F).
The coldest month (with the lowest average low temperature) is January (23.5°F).
Average pressure in September
Lake Saint Louis, 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
Lake Saint Louis, MO
- Average wind speed in September: 6mph
The windiest months (with the highest average wind speed) are January and February (8.9mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).
Average humidity in September
Lake Saint Louis, MO
- Average humidity in September: 74%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Lake Saint Louis, MO
- Average rainfall in September: 2.13"
The wettest month (with the highest rainfall) is April (3.82").
The driest month (with the least rainfall) is February (1.77").
Average rainfall days in September
Lake Saint Louis, MO
- Average rainfall days in September: 11.9 days
The month with the highest number of rainy days is May (17.2 days).
The month with the least rainy days is January (7.8 days).
Average snowfall in September
Lake Saint Louis, MO
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.15").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Lake Saint Louis, MO
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (7.3 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
Lake Saint Louis, MO
- Average daylight in September: 12h and 24min
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 36min
The months with the most sunshine are June and July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).
Average sunshine days in September
Lake Saint Louis, MO
- Average sunshine days in September: 15.8 days
The month with the most sunshine days is October (18.6 days).
The month with the least sunshine days is June (10.9 days).
Average UV index in September
Lake Saint Louis, 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
Lake Saint Louis, MO
- Average cloud cover in September: 29
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
Lake Saint Louis, 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).
