St. Louis Weather in September

September in St. Louis brings high temperatures around 27°C (81°F) during the day, dropping to 16°C (61°F) at night, with quite a bit of rainfall expected, averaging around 105 mm (4.1 in) for the month.

Rainfall in St. Louis in September

Historically, the month has about 9 days of rain, averaging 105 mm (4.1 in) in total. Individual showers can be quite heavy this month. A proper umbrella or rain jacket is worth having.

Temperature in St. Louis in September

Daytime highs in St. Louis in September reach 27°C (81°F), with nights around 16°C (61°F). Conditions stay fairly consistent through the month, making it easier to plan what to wear. Nights cool down to 16°C (61°F), so a light jacket or extra layer is useful once the sun goes down. On the plus side, the cooler nights make for comfortable sleeping conditions.

Sunshine in St. Louis in September

With approximately 235 hours of sunshine, the days are filled with clear skies. It makes it a perfect month for being outside.

If your ideal day consists of dry skies and pleasant temperatures, October typically offers the best circumstances for St. Louis.

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Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our St. Louis's climate page.

St. Louis Temperature in September

Min Temperature 16°C (61°F)  

Max Temperature 27°C (81°F)  

Chance of Rain 30%  

Precipitation 105 mm (4.1 in)  

Rainy days 9 days  

Humidity 71%  

Sunshine 235 hours  

Percentage Sunshine 63%  

What to Wear in St. Louis in September

Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). High rain levels are expected, so pack waterproof gear and an umbrella or poncho. Don't forget sun protection, sunglasses, sunscreen, and a hat. These are all good ideas with this much sunshine.

What To Do in St. Louis in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

9/10

Cycling

7/10

Walking

7/10

Camping

6/10

Outdoor sports

7/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit the United States of America, check out our St. Louis's climate page.

More climate data for St. Louis

Temperature Rainfall Sunshine Humidity

See the full St. Louis climate overview or explore weather in the United States of America.