Excessive Heat Watch 12:00 AM Heat Advisory — Knox, MO, Lewis, MO, Shelby, MO, Marion, MO, Monroe, MO, Ralls, MO, Pike, MO, Boone, MO, Audrain, MO, Moniteau, MO, Cole, MO, Osage, MO, Callaway, MO, Montgomery, MO, Lincoln, MO, Gasconade, MO, Crawford, MO, Washington, MO, St. Francois, MO, Iron, MO, Madison, MO, Reynolds, MO, Warren, MO, St. Charles, MO, Franklin, MO, St. Louis, MO, St. Louis City, MO, Jefferson, MO, Ste. Genevieve, MO 10:00 PM Excessive Heat Warning — 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, Ste. Genevieve, MO, Knox, MO, Lewis, MO, Shelby, MO, Marion, MO, Monroe, MO, Ralls, MO, Pike, MO, Audrain, MO, Lincoln, MO, Crawford, MO, Washington, MO, St. Francois, MO, Iron, MO, Madison, MO, Reynolds, MO 8:00 PM

Saint Charles County, Missouri, United States

Last updated: 6:59 PM CDT  ·  Refresh
32°C
Feels like 38°
Mostly Clear
▲ 35°  /  ▼ 23°
Wind
8 mph S
Humidity
60%
Dew Point
23°
Pressure
29.43 inHg
Visibility
10 mi
UV Index
3.8
Cloud Cover
24%
Sunrise
5:41 AM
Sunset
8:31 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Saint Charles County is currently mostly clear at 32°C. Dry conditions are expected through the next 24 hours. Atmospheric instability is elevated (CAPE up to 2730 J/kg) — isolated convective development possible. Sunrise: 5:41AM · Sunset: 8:31PM.

Alerts

Excessive Heat Watch
Expires 12:00 AM
Heat Advisory
Knox, MO, Lewis, MO, Shelby, MO, Marion, MO, Monroe, MO, Ralls, MO, Pike, MO, Boone, MO, Audrain, MO, Moniteau, MO, Cole, MO, Osage, MO, Callaway, MO, Montgomery, MO, Lincoln, MO, Gasconade, MO, Crawford, MO, Washington, MO, St. Francois, MO, Iron, MO, Madison, MO, Reynolds, MO, Warren, MO, St. Charles, MO, Franklin, MO, St. Louis, MO, St. Louis City, MO, Jefferson, MO, Ste. Genevieve, MO
Expires 10:00 PM
Excessive Heat Warning
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, Ste. Genevieve, MO, Knox, MO, Lewis, MO, Shelby, MO, Marion, MO, Monroe, MO, Ralls, MO, Pike, MO, Audrain, MO, Lincoln, MO, Crawford, MO, Washington, MO, St. Francois, MO, Iron, MO, Madison, MO, Reynolds, MO
Expires 8:00 PM
61 AQI · Moderate Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
32°
32%
7 PM
32°
48%
8 PM
30°
47%
9 PM
28°
39%
10 PM
27°
32%
11 PM
27°
31%
12 AM
26°
4%
1 AM
25°
4%
2 AM
24°
4%
3 AM
24°
5%
4 AM
24°
5%
5 AM
23°
8%
6 AM
23°
8%
7 AM
26°
10%
8 AM
27°
19%
9 AM
29°
19%
10 AM
31°
20%
11 AM
32°
20%
12 PM
33°
18%
1 PM
34°
18%
2 PM
34°
21%
3 PM
34°
21%
4 PM
34°
22%
5 PM
32°
22%
7-Day Forecast
Tonight
35° 23°
Mostly Clear with a 39% chance of rain.
Fri
36° 23°
Mostly Clear with a 29% chance of rain.
Sat
36° 24°
Mostly Clear with a 31% chance of rain.
Sun
33° 21°
Partly Cloudy with a 69% chance of rain.
Mon
33° 21°
Partly Cloudy with a 29% chance of rain.
Tue
32° 20°
Drizzle, 59% chance.
Wed
34° 21°
Rain, 63% chance.
TimeTempConditionsPrecipWindHumidity
Now 32° Mostly Clear 32% 8 mph S 60%
7 PM 32° Mostly Cloudy 48% 6 mph S 68%
8 PM 30° Mostly Cloudy 47% 7 mph S 76%
9 PM 28° Partly Cloudy 39% 8 mph SSW 82%
10 PM 27° Partly Cloudy 32% 8 mph SSW 82%
11 PM 27° Partly Cloudy 31% 6 mph SSW 82%
12 AM 26° Partly Cloudy 4% 6 mph SSW 82%
1 AM 25° Mostly Clear 4% 5 mph SSW 84%
2 AM 24° Partly Cloudy 4% 5 mph SSW 86%
3 AM 24° Mostly Clear 5% 5 mph SSW 89%
4 AM 24° Mostly Clear 5% 4 mph SSW 87%
5 AM 23° Clear 8% 5 mph S 87%
6 AM 23° Clear 8% 5 mph S 87%
7 AM 26° Clear 10% 6 mph SSW 81%
8 AM 27° Clear 19% 6 mph SSW 75%
9 AM 29° Clear 19% 7 mph SSW 68%
10 AM 31° Mostly Clear 20% 7 mph SSW 63%
11 AM 32° Mostly Clear 20% 7 mph SSW 58%
12 PM 33° Mostly Clear 18% 7 mph SW 52%
1 PM 34° Partly Cloudy 18% 7 mph SW 52%
2 PM 34° Partly Cloudy 21% 8 mph SW 52%
3 PM 34° Partly Cloudy 21% 8 mph WSW 52%
4 PM 34° Mostly Clear 22% 7 mph SW 55%
5 PM 32° Mostly Clear 22% 6 mph SW 59%
15-Day Forecast
Today
7/2
Mostly Clear
39%
23°
35°
Fri
7/3
Mostly Clear
29%
23°
36°
Sat
7/4
Mostly Clear
31%
24°
36°
Sun
7/5
Partly Cloudy
69%
21°
33°
Mon
7/6
Partly Cloudy
29%
21°
33°
Tue
7/7
Drizzle
59%
20°
32°
Wed
7/8
Rain
63%
21°
34°
Thu
7/9
Rain
63%
22°
34°
Fri
7/10
Thunderstorm
68%
22°
32°
Sat
7/11
Drizzle
68%
21°
34°
Sun
7/12
Drizzle
64%
20°
31°
Mon
7/13
Drizzle
60%
19°
31°
Tue
7/14
Drizzle
60%
19°
31°
Wed
7/15
Drizzle
60%
19°
32°
Thu
7/16
Drizzle
60%
20°
33°
61
Moderate
U.S. Air Quality Index · Dominant: PM2.5
50 100 150 200

Air quality is acceptable. Unusually sensitive people should consider limiting prolonged outdoor exertion.

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
Dominant
61 AQI 14.3 µg/m³
O3
Ground-level ozone
31 AQI 35 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Fri 61 Moderate 31 61
Sat 62 Moderate 29 62
Sun 63 Moderate 27 63
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 Thu Jul 2, 22:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE2983 J/kg
MLCAPE2445 J/kg
MUCAPE2983 J/kg
SBCIN-89 J/kg
MLCIN0 J/kg
Lifted Index-6.0
Kinematics
0–6 km Shear14 kt
0–1 km Shear8 kt
Eff. Shear13 kt
0–1 km SRH-10
0–3 km SRH-40
Eff. SRH-40
Storm Motion191° @ 27 kt
0–1 km EHI-0.2
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index34.9
Thermo & Levels
PWAT1.89 in
0–3 km LR7.0 °C/km
700–500 LR6.0 °C/km
Total Totals48.7
LCL874 hPa
LFC827 hPa
EL146 hPa
Freezing Lvl15,269 ft