5-day weather forecast St. Louis Sep 11, 2026

32°19° · Sunny

Weather forecast St. Louis Friday Sep 11, 2026: sunny, temperature from 19 °C to 32 °C.

Precipitation probability 16%. Wind up to 4.31 m/s (gusts 8.44 m/s). Air humidity 31–75%, atmospheric pressure 758–762 mm Hg, UV index up to 6.2.

Weather Alerts

WarningSep 7, 05:53 PM — Sep 9, 12:00 AMTranslate with Google

Air Quality Alert issued September 7 at 5:53PM 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 to 8 PM CDT Tuesday. 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/

WarningSep 7, 03:40 PM — Sep 8, 03:45 PMTranslate with Google

Air Quality Alert issued September 7 at 3:40PM CDT by NWS St Louis MO

Air Quality Alert

5 days at a glance — tap a day to open it

Sunrise 06:38
Sunset 19:15

New Moon0% illuminated
Moonrise 06:59 · Moonset 19:22

Chart

Table

← Thu, Sep 10

Fri, Sep 11, 2026

Sat, Sep 12 →

Forecast from 19 °C to 32 °C and precipitation

Temperature & Precipitation
Time	00:00	01:00	02:00	03:00	04:00	05:00	06:00	07:00	08:00	09:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00	19:00	20:00	21:00	22:00	23:00
Temperature (°C)	22	24	20	20	22	19	19	22	20	22	27	27	29	30	31	31	31	32	30	28	27	27	26	26
Precipitation (mm/hr)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

Cloud cover and precipitation probability

Cloud cover & Rain chance
Time	00:00	01:00	02:00	03:00	04:00	05:00	06:00	07:00	08:00	09:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00	19:00	20:00	21:00	22:00	23:00
Cloud cover (%)	0	5	0	9	49	5	5	5	89	100	5	100	100	89	95	100	100	5	5	5	30	0	0	5
Rain chance (%)	1	6	2	3	11	3	3	8	10	10	2	16	12	9	9	9	9	1	1	2	4	2	3	2

Wind speed and direction

Wind & Wind gust
Time	00:00	01:00	02:00	03:00	04:00	05:00	06:00	07:00	08:00	09:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00	19:00	20:00	21:00	22:00	23:00
Wind (m/s)	3	1.39	2.81	2.81	1.81	3	3.31	1.81	3.81	4.31	2.81	1.69	0.5	1.11	1.61	1.61	1.89	2.11	2.5	3	3.19	3	2.89	2.61
Wind gust (m/s)	7.22	2.03	6.61	6.64	3.11	7.31	8.31	3.14	8.44	7.53	4.5	4.69	1.11	1.33	1.61	4.61	5.89	2.31	6.5	5.11	6.03	6.33	6.92	6.03
Wind direction (°)	ESE 107°	WSW 237°	SE 131°	SE 141°	SSW 206°	SSE 151°	SSE 148°	S 181°	S 171°	S 170°	S 191°	SE 131°	SSE 165°	NE 40°	NE 38°	NE 34°	NE 44°	ENE 70°	ENE 62°	ENE 67°	E 81°	E 96°	ESE 107°	SE 143°

Air humidity

Humidity
Time	00:00	01:00	02:00	03:00	04:00	05:00	06:00	07:00	08:00	09:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00	19:00	20:00	21:00	22:00	23:00
Humidity (%)	45	71	52	54	72	55	56	75	51	43	49	65	53	43	37	33	31	35	40	49	53	55	58	47

Atmospheric pressure

Pressure
Time	00:00	01:00	02:00	03:00	04:00	05:00	06:00	07:00	08:00	09:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00	19:00	20:00	21:00	22:00	23:00
Pressure (mm Hg)	761	760	762	761	760	761	761	760	762	761	760	761	761	760	759	759	758	758	758	758	758	758	758	758

Ultraviolet index

UV Index
Time	00:00	01:00	02:00	03:00	04:00	05:00	06:00	07:00	08:00	09:00	10:00	11:00	12:00	13:00	14:00	15:00	16:00	17:00	18:00	19:00	20:00	21:00	22:00	23:00
UV Index	0	0	0	0	0	0	0	0	0.4	1.1	2.2	3.5	4.7	6.2	6.1	4.7	3	1.5	0.5	0	0	0	0	0

Air quality & pollen

Air quality is available for the first three days only.

← Thu, Sep 10

Fri, Sep 11, 2026

Sat, Sep 12 →

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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.

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