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Hourly Forecast
Daylight Hours
06:47
Sunrise
19:04
Sunset
Moon
Waxing Crescent
10:28
Moonrise
20:14
Moonset
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Weather in St. Louis tomorrow, September 15, 2026
St. Louis starts September 15, 2026 looking damp, with rain in the forecast and wetter spells likely at times. Waterproof kit is the safer call for early plans. Morning skies stay relatively clear, holding cloud close to 0% near 00:00. The early part of the day favours being outside.
The temperature range runs from about 21°C up to 37°C. Expect humidity between 43% and 91%, most humid near 07:00. Expect gentle winds, highest near 09:00 at 3.9 km/h.
Afternoon skies stay clogged, peaking close to 80% near 12:00. The grey theme continues rather than clearing out. Horizontal visibility holds close to 16.1 km. Expect sunrise at 06:48, sunset at 19:02, and 12 hours 14 minutes of sunlight today overall.
In short, treat September 15, 2026 in St. Louis as a damp day: pack covers, watch the wetter hours, and expect a high near 37°C.
Frequently asked questions about weather in St. Louis
How warm does it get in St. Louis?
The warmest month in St. Louis is July, with average high temperatures of 31°C. The average temperature during this period is around 26°C.
How cold does it get in St. Louis?
The coldest month in St. Louis is January, with average low temperatures of -3°C. The average temperature during this period is around 0°C.
What is the wettest time of year in St. Louis?
The wettest month in St. Louis is April, with an average of 129mm of precipitation.
What is the driest time of year in St. Louis?
The driest month in St. Louis is December, with an average of 59mm of precipitation.
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