Hourly Weather | Today Tuesday, June 9, 2026
Active Weather Warnings
St. Charles, Missouri
9 PM
Cloudy Night
86°
Feels Like 95°
6
Humidity: 70%
UV Index: 0
Wind: 6 mph
10 PM
Cloudy Night
84°
Feels Like 91°
6
Humidity: 75%
UV Index: 0
Wind: 6 mph
11 PM
Cloudy Night
81°
Feels Like 90°
6
Humidity: 80%
UV Index: 0
Wind: 6 mph

Hourly Air Quality Forecast - AQI (US EPA)

9 PM
20 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.13 µg/m³
  • PM10: 2.71 µg/m³
  • O3: 0.022 ppm
  • NO2: 0.4 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

10 PM
19 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.2 µg/m³
  • PM10: 2.86 µg/m³
  • O3: 0.021 ppm
  • NO2: 0.4 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

11 PM
19 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 2.25 µg/m³
  • PM10: 2.99 µg/m³
  • O3: 0.020 ppm
  • NO2: 0.4 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Weather Alerts and Warnings for St. Charles

Severe Immediate Observed

Flood Warning

Flood Warning issued June 9 at 10:43AM CDT until June 11 at 11:17PM CDT by NWS St Louis MO
Jun 9, 10:43 AM Jun 11, 11:17 PM
...The Flood Warning continues for the following rivers in
Missouri...

Missouri River at St. Charles.

Missouri River at Washington.

Missouri River at Hermann.

...The Flood Warning is extended for the following rivers in
Missouri...

Missouri River at Jefferson City.

Missouri River near Chamois.

River forecasts are based on observed precipitation and forecast
precipitation for the next 24 hours.

WHAT: Minor flooding is occurring and minor flooding is forecast.

WHERE: Missouri River at St. Charles.

WHEN: Until Thursday evening.

IMPACTS: At 27.0 feet, The Katy Trail begins flooding near this
height along Hawning Road, about 2 miles north northeast of the
Highway 370 bridge.

ADDITIONAL DETAILS:
- At 10:00 AM CDT Tuesday the stage was 26.8 feet.
- Recent Activity...The maximum river stage in the 24 hours ending
at 10:00 AM CDT Tuesday was 26.8 feet.
- Forecast...The river is expected to rise to a crest of 27.1 feet
this evening. It will then fall below flood stage tomorrow
afternoon.
- Flood stage is 25.0 feet.
+ Read More
Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles. This product, along with additional weather and stream information, is available at https://water.noaa.gov/wfo/lsx
Updated: Jun 9, 7:32 PM Source: NWS Alert
Moderate Expected Likely

Heat Advisory

Heat Advisory issued June 9 at 2:50PM CDT until June 9 at 10:00PM CDT by NWS St Louis MO
Jun 9, 2:50 PM Jun 9, 10:00 PM
WHAT: Heat index values up to 105.

WHERE: Portions of southwest Illinois and central, east central,
and southeast Missouri.

WHEN: Until 10 PM CDT this evening.

IMPACTS: Hot temperatures and high humidity may cause heat
illnesses.
+ Read More
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances. Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose fitting clothing when possible. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
Updated: Jun 9, 7:32 PM Source: NWS Alert