5-day weather forecast St. Louis Sep 11, 2026
31°Weather forecast St. Louis Friday Sep 11, 2026: overcast, temperature from 20 °C to 31 °C.
Precipitation probability 46%. Wind up to 3.19 m/s (gusts 8.33 m/s). Air humidity 38–98%, atmospheric pressure 758–761 mm Hg, UV index up to 5.6.
Weather Alerts
Air Quality Alert issued September 8 at 1:42AM CDT by NWS St Louis MO
Air Quality Alert
The St. Louis Clean Air Partnership has issued an air quality alert
for the St. Louis metropolitan area from 10 AM this morning to 8 PM
CDT this evening.
An Orange air quality forecast means that maximum ozone
concentrations are expected to reach levels that pose a health risk.
Adverse health effects increase as air quality deteriorates. Ground-
level ozone is an air contaminant which can cause breathing
difficulties for children, older adults, as well as persons with
respiratory problems.
Reducing outdoor physical activity is recommended. If it is a
regularly scheduled work day you are urged to consider
telecommuting, carpooling, or utilizing public transit. Avoid
excessive idling and do not top off when refueling motor vehicles.
The use of gasoline-powered lawn equipment should be reduced or
postponed until late in the day.
For more information visit the St. Louis Clean Air Partnership at
http://cleanair-stlouis.com/
For current Air Quality Index (AQI) values visit
https://www.airnow.gov/
5 days at a glance — tap a day to open it
Sunrise 06:38
Sunset 19:15
Sunset 19:15
New Moon0% illuminated
Moonrise 06:59 · Moonset 19:22
Moonrise 06:59 · Moonset 19:22
Chart
Table
| Time | Weather | Temperature | Rain chance | Cloud cover | Humidity | Pressure | Wind | UV Index |
|---|---|---|---|---|---|---|---|---|
| 00:00 |  Fog | 23 °C | 46% (0.04 mm/hr) | 100% | 97% | 761 mm Hg | WSW 244° 0.69 (0.81) m/s | 0 |
| 01:00 |  Mist | 23 °C | 41% (0.02 mm/hr) | 100% | 97% | 761 mm Hg | NW 323° 0.81 (0.92) m/s | 0 |
| 02:00 | Fog | 22 °C | 43% (0.01 mm/hr) | 100% | 98% | 761 mm Hg | N 5° 1 (1.11) m/s | 0 |
| 03:00 | Fog | 22 °C | 43% | 100% | 98% | 761 mm Hg | N 4° 1.31 (1.33) m/s | 0 |
| 04:00 | Fog | 22 °C | 43% (0.01 mm/hr) | 100% | 98% | 761 mm Hg | NNE 18° 1.81 (2.33) m/s | 0 |
| 05:00 | Fog | 21 °C | 43% (0.01 mm/hr) | 100% | 97% | 761 mm Hg | NNE 33° 1.81 (2.42) m/s | 0 |
| 06:00 | Mist | 20 °C | 37% | 97% | 95% | 761 mm Hg | NE 41° 2 (2.72) m/s | 0 |
| 07:00 |  Mist | 20 °C | 38% | 99% | 95% | 761 mm Hg | NE 51° 2.31 (3.25) m/s | 0 |
| 08:00 | Overcast | 20 °C | 30% | 100% | 90% | 761 mm Hg | ENE 61° 2 (2.64) m/s | 0.4 |
| 09:00 | Overcast | 21 °C | 25% | 100% | 83% | 761 mm Hg | ENE 71° 1.69 (1.75) m/s | 1.2 |
| 10:00 | Overcast | 23 °C | 21% | 100% | 76% | 761 mm Hg | E 84° 1.61 (4.61) m/s | 2.6 |
| 11:00 | Overcast | 25 °C | 16% | 100% | 67% | 761 mm Hg | ESE 112° 1.61 (1.61) m/s | 4.2 |
| 12:00 | Overcast | 27 °C | 14% | 100% | 59% | 761 mm Hg | SE 138° 1.5 (1.72) m/s | 5.6 |
| 13:00 | Overcast | 29 °C | 12% | 100% | 53% | 761 mm Hg | SSE 165° 1.69 (2.22) m/s | 5.4 |
| 14:00 | Overcast | 30 °C | 11% | 98% | 46% | 760 mm Hg | S 180° 1.89 (2.31) m/s | 5.5 |
| 15:00 |  Cloudy | 31 °C | 6% | 67% | 42% | 759 mm Hg | S 182° 1.89 (2.11) m/s | 4.2 |
| 16:00 | Overcast | 31 °C | 9% | 97% | 39% | 758 mm Hg | S 176° 2 (2.31) m/s | 2.1 |
| 17:00 | Overcast | 31 °C | 10% | 100% | 38% | 758 mm Hg | SSE 163° 2 (2.5) m/s | 1.1 |
| 18:00 |  Sunny | 30 °C | 1% | 10% | 43% | 758 mm Hg | SE 128° 1.5 (2.03) m/s | 0.4 |
| 19:00 | Sunny | 29 °C | 2% | 0% | 50% | 758 mm Hg | E 101° 2.5 (3.89) m/s | 0 |
| 20:00 |  Clear | 28 °C | 3% | 0% | 58% | 758 mm Hg | E 101° 3.11 (6.61) m/s | 0 |
| 21:00 | Clear | 26 °C | 4% | 0% | 62% | 758 mm Hg | ESE 110° 3.19 (8.11) m/s | 0 |
| 22:00 | Clear | 25 °C | 4% | 0% | 64% | 758 mm Hg | SE 126° 2.89 (8.33) m/s | 0 |
| 23:00 | Clear | 25 °C | 4% | 0% | 65% | 758 mm Hg | SE 126° 2.89 (8.22) m/s | 0 |
St. Louis on the map
Data Sources & Methodology
Our weather forecasts are powered by a professional weather data provider that aggregates data from national weather services, satellite observations, radar networks, and over 80,000 weather stations worldwide. Forecast data is updated multiple times daily. We convert raw data into clear summaries — wind speed in m/s, pressure in mmHg — so you can plan your day with confidence.