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

Jefferson County, Missouri, United States

Last updated: 6:58 PM CDT  ·  Refresh
32°C
Feels like 38°
Mostly Clear
▲ 36°  /  ▼ 22°
Wind
8 mph S
Humidity
63%
Dew Point
23°
Pressure
29.31 inHg
Visibility
10 mi
UV Index
3.8
Cloud Cover
18%
Sunrise
5:43 AM
Sunset
8:29 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Jefferson County is currently mostly clear at 32°C. Dry conditions are expected through the next 24 hours. Atmospheric instability is elevated (CAPE up to 2697 J/kg) — isolated convective development possible. Sunrise: 5:43AM · Sunset: 8:29PM.

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
56 AQI · Moderate Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
32°
30%
7 PM
31°
48%
8 PM
29°
47%
9 PM
27°
27%
10 PM
26°
26%
11 PM
26°
19%
12 AM
25°
12%
1 AM
24°
7%
2 AM
24°
8%
3 AM
23°
8%
4 AM
24°
8%
5 AM
22°
8%
6 AM
22°
8%
7 AM
24°
22%
8 AM
26°
30%
9 AM
30°
31%
10 AM
31°
28%
11 AM
32°
28%
12 PM
33°
26%
1 PM
34°
27%
2 PM
34°
27%
3 PM
33°
28%
4 PM
33°
31%
5 PM
32°
22%
7-Day Forecast
Tonight
36° 22°
Mostly Clear with a 30% chance of rain.
Fri
36° 22°
Mostly Clear with a 31% chance of rain.
Sat
36° 22°
Partly Cloudy with a 37% chance of rain.
Sun
34° 19°
Mostly Cloudy with a 40% chance of rain.
Mon
34° 20°
Thunderstorm, 51% chance.
Tue
34° 19°
Drizzle, 59% chance.
Wed
34° 19°
Drizzle, 52% chance.
TimeTempConditionsPrecipWindHumidity
Now 32° Mostly Clear 30% 8 mph S 63%
7 PM 31° Partly Cloudy 48% 6 mph SSE 71%
8 PM 29° Partly Cloudy 47% 4 mph S 76%
9 PM 27° Partly Cloudy 27% 5 mph SSW 80%
10 PM 26° Partly Cloudy 26% 4 mph SSW 82%
11 PM 26° Partly Cloudy 19% 4 mph SSW 82%
12 AM 25° Partly Cloudy 12% 4 mph SSW 83%
1 AM 24° Partly Cloudy 7% 3 mph SSW 85%
2 AM 24° Mostly Cloudy 8% 3 mph SSW 87%
3 AM 23° Partly Cloudy 8% 3 mph SSW 89%
4 AM 24° Partly Cloudy 8% 2 mph S 87%
5 AM 22° Mostly Clear 8% 3 mph S 87%
6 AM 22° Clear 8% 3 mph S 87%
7 AM 24° Mostly Clear 22% 4 mph SSW 79%
8 AM 26° Mostly Clear 30% 5 mph SSW 71%
9 AM 30° Mostly Clear 31% 6 mph SSW 62%
10 AM 31° Mostly Clear 28% 6 mph SSW 57%
11 AM 32° Partly Cloudy 28% 6 mph SSW 52%
12 PM 33° Partly Cloudy 26% 6 mph SSW 47%
1 PM 34° Partly Cloudy 27% 5 mph SSW 49%
2 PM 34° Partly Cloudy 27% 6 mph SSW 52%
3 PM 33° Mostly Cloudy 28% 6 mph SSW 54%
4 PM 33° Partly Cloudy 31% 6 mph SSW 56%
5 PM 32° Partly Cloudy 22% 5 mph SSW 57%
15-Day Forecast
Today
7/2
Mostly Clear
30%
22°
36°
Fri
7/3
Mostly Clear
31%
22°
36°
Sat
7/4
Partly Cloudy
37%
22°
36°
Sun
7/5
Mostly Cloudy
40%
19°
34°
Mon
7/6
Thunderstorm
51%
20°
34°
Tue
7/7
Drizzle
59%
19°
34°
Wed
7/8
Drizzle
52%
19°
34°
Thu
7/9
Rain
63%
22°
35°
Fri
7/10
Thunderstorm
68%
21°
34°
Sat
7/11
Overcast
44%
21°
35°
Sun
7/12
Rain
68%
20°
32°
Mon
7/13
Drizzle
60%
19°
33°
Tue
7/14
Clear
60%
19°
33°
Wed
7/15
Drizzle
60%
19°
33°
Thu
7/16
Drizzle
60%
21°
34°
56
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
56 AQI 11.7 µg/m³
O3
Ground-level ozone
29 AQI 32 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Fri 56 Moderate 29 56
Sat 53 Moderate 28 53
Sun 54 Moderate 27 54
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
SBCAPE2968 J/kg
MLCAPE2575 J/kg
MUCAPE2968 J/kg
SBCIN-81 J/kg
MLCIN0 J/kg
Lifted Index-6.1
Kinematics
0–6 km Shear9 kt
0–1 km Shear9 kt
Eff. Shear8 kt
0–1 km SRH-17
0–3 km SRH-37
Eff. SRH-37
Storm Motion183° @ 25 kt
0–1 km EHI-0.3
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index33.8
Thermo & Levels
PWAT1.82 in
0–3 km LR7.1 °C/km
700–500 LR6.0 °C/km
Total Totals49.1
LCL869 hPa
LFC819 hPa
EL147 hPa
Freezing Lvl15,151 ft