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: 7:59 PM CDT  ·  Refresh
31°C
Feels like 37°
Partly Cloudy
▲ 35°  /  ▼ 23°
Wind
7 mph S
Humidity
68%
Dew Point
23°
Pressure
29.44 inHg
Visibility
10 mi
UV Index
1.5
Cloud Cover
43%
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 partly cloudy at 31°C. Dry conditions are expected through the next 24 hours. Atmospheric instability is elevated (CAPE up to 2938 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
31°
32%
8 PM
30°
48%
9 PM
28°
39%
10 PM
27°
32%
11 PM
27°
32%
12 AM
26°
4%
1 AM
25°
4%
2 AM
24°
4%
3 AM
24°
4%
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°
19%
11 AM
32°
17%
12 PM
33°
18%
1 PM
34°
18%
2 PM
35°
21%
3 PM
34°
21%
4 PM
34°
21%
5 PM
33°
22%
6 PM
33°
26%
7-Day Forecast
Tonight
35° 23°
Partly Cloudy with a 32% chance of rain.
Fri
36° 23°
Mostly Clear with a 29% chance of rain.
Sat
36° 23°
Clear with a 38% chance of rain.
Sun
33° 21°
Mostly Cloudy with a 69% chance of rain.
Mon
33° 21°
Partly Cloudy with a 29% chance of rain.
Tue
33° 19°
Drizzle, 59% chance.
Wed
34° 21°
Rain, 63% chance.
TimeTempConditionsPrecipWindHumidity
Now 31° Partly Cloudy 32% 7 mph S 68%
8 PM 30° Mostly Cloudy 48% 7 mph S 75%
9 PM 28° Partly Cloudy 39% 9 mph SSW 82%
10 PM 27° Partly Cloudy 32% 8 mph SSW 81%
11 PM 27° Mostly Cloudy 32% 7 mph SSW 81%
12 AM 26° Partly Cloudy 4% 6 mph SSW 82%
1 AM 25° Partly Cloudy 4% 5 mph SSW 84%
2 AM 24° Partly Cloudy 4% 5 mph SSW 86%
3 AM 24° Mostly Clear 4% 5 mph SSW 89%
4 AM 24° Mostly Clear 5% 4 mph S 87%
5 AM 23° Clear 8% 5 mph S 88%
6 AM 23° Clear 8% 5 mph S 87%
7 AM 26° Clear 10% 6 mph SSW 80%
8 AM 27° Clear 19% 6 mph SSW 74%
9 AM 29° Clear 19% 7 mph SSW 68%
10 AM 31° Mostly Clear 19% 7 mph SSW 62%
11 AM 32° Mostly Clear 17% 7 mph SSW 57%
12 PM 33° Mostly Clear 18% 7 mph SW 52%
1 PM 34° Partly Cloudy 18% 7 mph SW 51%
2 PM 35° Partly Cloudy 21% 8 mph SW 50%
3 PM 34° Partly Cloudy 21% 9 mph WSW 50%
4 PM 34° Mostly Clear 21% 7 mph SW 54%
5 PM 33° Mostly Clear 22% 6 mph SSW 58%
6 PM 33° Clear 26% 6 mph SSW 62%
15-Day Forecast
Today
7/2
Partly Cloudy
32%
23°
35°
Fri
7/3
Mostly Clear
29%
23°
36°
Sat
7/4
Clear
38%
23°
36°
Sun
7/5
Mostly Cloudy
69%
21°
33°
Mon
7/6
Partly Cloudy
29%
21°
33°
Tue
7/7
Drizzle
59%
19°
33°
Wed
7/8
Rain
63%
21°
34°
Thu
7/9
Rain
63%
21°
34°
Fri
7/10
Thunderstorm
68%
22°
32°
Sat
7/11
Thunderstorm
68%
21°
36°
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
Today 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, 23:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE2927 J/kg
MLCAPE2260 J/kg
MUCAPE2927 J/kg
SBCIN-131 J/kg
MLCIN0 J/kg
Lifted Index-6.1
Kinematics
0–6 km Shear13 kt
0–1 km Shear9 kt
Eff. Shear12 kt
0–1 km SRH-13
0–3 km SRH-39
Eff. SRH-39
Storm Motion194° @ 27 kt
0–1 km EHI-0.2
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index32.3
Thermo & Levels
PWAT1.81 in
0–3 km LR6.5 °C/km
700–500 LR6.3 °C/km
Total Totals48.6
LCL890 hPa
LFC811 hPa
EL146 hPa
Freezing Lvl15,397 ft