Extreme Heat Warning — Clinton, IL, Washington, IL, Randolph, IL, Madison, IL, St. Clair, IL, Monroe, IL, Boone, MO, Moniteau, MO, Cole, MO, Osage, MO, Callaway, MO, Montgomery, MO, Gasconade, MO, Warren, MO, St. Charles, MO, Franklin, MO, St. Louis, MO, St. Louis City, MO, Jefferson, MO 8:00 PM

Saint Charles County, Missouri, United States

Last updated: 5:16 AM CDT  ·  Refresh
26°C
Feels like 27°
Mostly Clear
▲ 36°  /  ▼ 24°
Wind
8 mph SSW
Humidity
74%
Dew Point
22°
Pressure
29.39 inHg
Visibility
10 mi
UV Index
0.0
Cloud Cover
15%
Sunrise
6:12 AM
Sunset
8:02 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Saint Charles County is currently mostly clear at 26°C. Dry conditions are expected through the next 24 hours. Atmospheric instability is elevated (CAPE up to 2867 J/kg) — isolated convective development possible. Sunrise: 6:12AM · Sunset: 8:02PM.

Alerts

Extreme Heat Warning
Clinton, IL, Washington, IL, Randolph, IL, Madison, IL, St. Clair, IL, Monroe, IL, Boone, MO, Moniteau, MO, Cole, MO, Osage, MO, Callaway, MO, Montgomery, MO, Gasconade, MO, Warren, MO, St. Charles, MO, Franklin, MO, St. Louis, MO, St. Louis City, MO, Jefferson, MO
Expires 8:00 PM
39 AQI · Good Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
26°
7%
6 AM
24°
21%
7 AM
24°
20%
8 AM
26°
20%
9 AM
27°
20%
10 AM
29°
20%
11 AM
30°
14%
12 PM
32°
14%
1 PM
34°
3%
2 PM
34°
4%
3 PM
35°
4%
4 PM
35°
12%
5 PM
36°
13%
6 PM
34°
16%
7 PM
33°
21%
8 PM
31°
30%
9 PM
30°
30%
10 PM
29°
22%
11 PM
28°
22%
12 AM
27°
23%
1 AM
27°
23%
2 AM
27°
24%
3 AM
27°
24%
4 AM
26°
24%
7-Day Forecast
Today
36° 24°
Partly Cloudy with a 30% chance of rain.
Wed
36° 24°
Partly Cloudy with a 43% chance of rain.
Thu
35° 24°
Partly Cloudy with a 56% chance of rain.
Fri
34° 22°
Clear with a 32% chance of rain.
Sat
39° 24°
Partly Cloudy.
Sun
38° 22°
Drizzle, 47% chance.
Mon
33° 21°
Clear with a 47% chance of rain.
TimeTempConditionsPrecipWindHumidity
Now 26° Mostly Clear 7% 8 mph SSW 74%
6 AM 24° Mostly Clear 21% 9 mph SW 71%
7 AM 24° Mostly Clear 20% 9 mph SW 70%
8 AM 26° Partly Cloudy 20% 10 mph SW 66%
9 AM 27° Mostly Cloudy 20% 11 mph SW 62%
10 AM 29° Partly Cloudy 20% 11 mph SW 57%
11 AM 30° Partly Cloudy 14% 11 mph SW 53%
12 PM 32° Partly Cloudy 14% 11 mph SW 49%
1 PM 34° Mostly Clear 3% 12 mph SW 45%
2 PM 34° Partly Cloudy 4% 11 mph SW 43%
3 PM 35° Partly Cloudy 4% 11 mph SW 42%
4 PM 35° Partly Cloudy 12% 11 mph SW 42%
5 PM 36° Mostly Clear 13% 10 mph SW 46%
6 PM 34° Mostly Clear 16% 8 mph SW 50%
7 PM 33° Partly Cloudy 21% 7 mph SSW 53%
8 PM 31° Partly Cloudy 30% 6 mph SSW 56%
9 PM 30° Mostly Cloudy 30% 6 mph SSW 59%
10 PM 29° Mostly Cloudy 22% 6 mph SSW 61%
11 PM 28° Partly Cloudy 22% 6 mph SSW 64%
12 AM 27° Partly Cloudy 23% 7 mph SSW 66%
1 AM 27° Partly Cloudy 23% 7 mph SSW 69%
2 AM 27° Partly Cloudy 24% 6 mph SSW 70%
3 AM 27° Partly Cloudy 24% 6 mph SSW 70%
4 AM 26° Partly Cloudy 24% 6 mph SSW 71%
15-Day Forecast
Today
8/11
Partly Cloudy
30%
24°
36°
Wed
8/12
Partly Cloudy
43%
24°
36°
Thu
8/13
Partly Cloudy
56%
24°
35°
Fri
8/14
Clear
32%
22°
34°
Sat
8/15
Partly Cloudy
15%
24°
39°
Sun
8/16
Drizzle
47%
22°
38°
Mon
8/17
Clear
47%
21°
33°
Tue
8/18
Rain
53%
20°
38°
Wed
8/19
Mostly Cloudy
35%
23°
38°
Thu
8/20
Mostly Clear
35%
24°
39°
Fri
8/21
Clear
60%
21°
39°
Sat
8/22
Drizzle
60%
21°
35°
Sun
8/23
Clear
60%
21°
35°
Mon
8/24
Drizzle
60%
20°
32°
Tue
8/25
Drizzle
60%
19°
33°
39
Good
U.S. Air Quality Index · Dominant: PM2.5
50 100 150 200

Air quality is satisfactory and poses little or no health risk.

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
Dominant
39 AQI 7.1 µg/m³
O3
Ground-level ozone
35 AQI 38 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Today 39 Good 35 39
Wed 35 Good 35 24
Thu 36 Good 32 36
About the Air Quality Index
0–50 Good
51–100 Moderate
101–150 Unhealthy for Sensitive Groups
151–200 Unhealthy
201–300 Very Unhealthy
301–500 Hazardous

The U.S. AQI runs 0–500. The overall value equals the highest individual pollutant sub-index, and the dominant pollutant is the one driving it. PM2.5 (fine particles) is reported in µg/m³ and ozone (O3) in ppb. Forecast source: NWS NAQFC.

1000850700500400300250200150100 -40-30-20-10010203040 0.41247101624 LCLLFCEL0°C Temperature (°C) Pressure (hPa)
Temp Dewpoint Parcel (SB) CAPE CIN Dry adiabat Moist adiabat Mixing ratio
RAP
Valid Tue Aug 11, 09:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE1392 J/kg
MLCAPE1336 J/kg
MUCAPE1392 J/kg
SBCIN-504 J/kg
MLCIN0 J/kg
Lifted Index-6.3
Kinematics
0–6 km Shear19 kt
0–1 km Shear19 kt
Eff. Shear12 kt
0–1 km SRH157
0–3 km SRH144
Eff. SRH-18
Storm Motion310° @ 17 kt
0–1 km EHI1.4
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index28.0
Thermo & Levels
PWAT1.55 in
0–3 km LR4.1 °C/km
700–500 LR8.4 °C/km
Total Totals55.5
LCL940 hPa
LFC649 hPa
EL195 hPa
Freezing Lvl14,669 ft