Normal weather for Saint Louis in September
It's warm in September in Saint Louis with an average temperature of 29°C. Temperatures this month range from a low of 26°C to a high of 32°C. At night, you can expect temperatures between 14°C and 20°C.
In September, there is an average of 130 mm of precipitation, spread over 12 days. The wind speed is around 3 Bft, mostly coming from the South.
Saint Louis in September |
London | ||
|---|---|---|---|
 Average Temperature |
29°C | 20°C | |
 High Temp |
32°C | 22°C | |
| Low Temp |
26°C | 17°C | |
 Total Precipitation |
130 mm | 44 mm | |
| Rainy Days |
12 days | 8 days | |
Start of September
The month of September starts in Saint Louis with hot temperatures, averaging around 30°C during the day and nights close to 20°C. You can expect regular precipitation, but there’s also a chance for some sunny days in the first days of the month.
Since temperatures can differ between day and night, it’s a good idea to dress in layers. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal for the day. In the evening and morning, a T-shirt, light trousers or skirt, and a light jacket are recommended.
Mid-September
By mid-September, the average daytime temperature rises to around 31°C, with nights close to 18°C. There might be a few showers during this period, but plenty of dry days with sunshine too.
Temperatures vary between day and night, so it’s smart to wear layers. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal for the day. In the evening and morning, a T-shirt, light trousers or skirt, and a light jacket are recommended.
End of September
By the end of September, the average daytime temperature in Saint Louis will be around 28°C, with nights close to 16°C. A shower might show up, but overall the weather will be dry and sunny.
As it gets cooler in the evening, it’s best to wear layers. Breezy clothes like shorts or a dress, plus a hat and sunglasses, are ideal for the day. For the evening and morning, a shirt, maybe a light cardigan, and light trousers will do.
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UV index
The UV index is a maximum of 7 this month. That's a moderate to high value on the intensity scale of 1 to 11. Unprotected skin can burn within 15-25 minutes.
Is September a good time to visit Saint Louis?
After some sun? Then September isn’t the best time to be in Saint Louis. The temperature is pleasant, but there’s too much chance of rain this month.
Temperature records for Saint Louis in September
With 37°C, Saint Louis hit the highest temperature in the last 10 years in September 2017. The lowest daytime temperature in this month was 15°C in 2014. The extreme night temperatures ranged from a low of 5°C to a high of 25°C.
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Daily Temperature in September in Saint Louis
This chart shows the average daily temperatures, both day and night, for each day in September in Saint Louis, measured in degrees Celsius. The red line represents the maximum temperatures, while the blue line shows the minimums. The days of the month are displayed at the bottom of the chart. The data, based on historical observations, gives an overview of the average daily temperatures during this month.
Daily Precipitation in September in Saint Louis
The chart below shows the average daily precipitation in September for Saint Louis, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail. The days of the month are shown at the bottom of the chart.
A low average precipitation means that the chance of rain on that day is usually small, while a higher average suggests that rain is more likely. But it’s still an average, so each day can be different. Based on historical weather data for September, you can expect around 12 days of rain in Saint Louis.
Daily UV Index in September in Saint Louis
This chart shows the average daily UV index in September in Saint Louis, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Temperature in September in Saint Louis Over the Years
This chart shows the average temperature in September in Saint Louis, measured in degrees Celsius, over the past years.
Total Precipitation in September in Saint Louis Over the Years
This chart shows the average precipitation in September in Saint Louis, measured in millimetres over the past years. Precipitation is always measured as water, even if it’s snow or hail.
Daily climate in September for Saint Louis
Click on a specific day in September for detailed info on the typical weather on that day in Saint Louis. Check out the historical temperatures and precipitation over the past 10 years on this day.
Weather experiences in September in Saint Louis
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Average Weather in Saint Louis by Month
Click on a month below to see detailed weather info for Saint Louis. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.
Or check out the climate of Saint Louis for all months at once
