Heat Advisory — Grayson, TX, Fannin, TX, Lamar, TX, Denton, TX, Collin, TX, Hunt, TX, Delta, TX, Hopkins, TX, Tarrant, TX, Dallas, TX, Rockwall, TX, Kaufman, TX, Van Zandt, TX, Rains, TX, Johnson, TX, Ellis, TX, Henderson, TX, Hill, TX, Navarro, TX, Freestone, TX, Anderson, TX, Bell, TX, McLennan, TX, Falls, TX, Limestone, TX, Leon, TX, Milam, TX, Robertson, TX 8:00 PM

Johnson County, Texas, United States

Last updated: 3:47 PM CDT  ·  Refresh
36°C
Feels like 39°
Clear
▲ 38°  /  ▼ 23°
Wind
12 mph S
Humidity
39%
Dew Point
20°
Pressure
29,07 inHg
Visibility
10 mi
UV Index
8,0
Cloud Cover
9%
Sunrise
7:11 AM
Sunset
7:37 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Johnson County is currently clear at 36°C. Dry conditions are expected through the next 24 hours. Atmospheric instability is elevated (CAPE up to 1621 J/kg) — isolated convective development possible. Sunrise: 7:11AM · Sunset: 7:37PM.

Alerts

Heat Advisory
Grayson, TX, Fannin, TX, Lamar, TX, Denton, TX, Collin, TX, Hunt, TX, Delta, TX, Hopkins, TX, Tarrant, TX, Dallas, TX, Rockwall, TX, Kaufman, TX, Van Zandt, TX, Rains, TX, Johnson, TX, Ellis, TX, Henderson, TX, Hill, TX, Navarro, TX, Freestone, TX, Anderson, TX, Bell, TX, McLennan, TX, Falls, TX, Limestone, TX, Leon, TX, Milam, TX, Robertson, TX
Expires 8:00 PM
35 AQI · Good Dominant: O3 Air Quality
Hourly Forecast · Next 24 Hours
Now
36°
3%
4 PM
37°
3%
5 PM
37°
3%
6 PM
36°
3%
7 PM
34°
3%
8 PM
32°
3%
9 PM
31°
3%
10 PM
30°
3%
11 PM
29°
3%
12 AM
28°
3%
1 AM
28°
3%
2 AM
27°
3%
3 AM
27°
3%
4 AM
26°
3%
5 AM
23°
3%
6 AM
23°
3%
7 AM
23°
3%
8 AM
25°
3%
9 AM
27°
3%
10 AM
29°
3%
11 AM
30°
3%
12 PM
31°
3%
1 PM
33°
3%
2 PM
34°
3%
7-Day Forecast
Today
38° 23°
Clear.
Mon
39° 23°
Clear.
Tue
39° 21°
Mostly Clear.
Wed
36° 21°
Clear.
Thu
36° 24°
Clear.
Fri
36° 24°
Clear.
Sat
36° 23°
Clear.
TimeTempConditionsPrecipWindHumidity
Now 36° Clear 3% 12 mph S 39%
4 PM 37° Clear 3% 12 mph S 38%
5 PM 37° Clear 3% 12 mph SSE 37%
6 PM 36° Clear 3% 12 mph SSE 37%
7 PM 34° Clear 3% 11 mph SSE 41%
8 PM 32° Clear 3% 10 mph SSE 47%
9 PM 31° Clear 3% 10 mph SSE 52%
10 PM 30° Clear 3% 10 mph SSE 56%
11 PM 29° Clear 3% 11 mph SSE 60%
12 AM 28° Clear 3% 11 mph S 67%
1 AM 28° Clear 3% 11 mph S 72%
2 AM 27° Clear 3% 10 mph S 75%
3 AM 27° Clear 3% 9 mph S 78%
4 AM 26° Clear 3% 9 mph S 80%
5 AM 23° Mostly Clear 3% 8 mph S 82%
6 AM 23° Mostly Clear 3% 8 mph S 84%
7 AM 23° Mostly Clear 3% 9 mph S 80%
8 AM 25° Mostly Clear 3% 10 mph SSW 72%
9 AM 27° Clear 3% 11 mph SSW 66%
10 AM 29° Clear 3% 11 mph SSW 61%
11 AM 30° Clear 3% 11 mph SSW 56%
12 PM 31° Clear 3% 11 mph SSW 51%
1 PM 33° Clear 3% 11 mph S 48%
2 PM 34° Clear 3% 12 mph S 47%
15-Day Forecast
Today
9/13
Clear
3%
23°
38°
Mon
9/14
Clear
3%
23°
39°
Tue
9/15
Mostly Clear
8%
21°
39°
Wed
9/16
Clear
8%
21°
36°
Thu
9/17
Clear
3%
24°
36°
Fri
9/18
Clear
3%
24°
36°
Sat
9/19
Clear
19%
23°
36°
Sun
9/20
Clear
60%
23°
34°
Mon
9/21
Drizzle
60%
19°
33°
Tue
9/22
Drizzle
60%
18°
33°
Wed
9/23
Drizzle
60%
21°
32°
Thu
9/24
Drizzle
60%
21°
32°
Fri
9/25
Clear
60%
21°
32°
Sat
9/26
Clear
60%
21°
32°
Sun
9/27
Drizzle
60%
21°
32°
35
Good
U.S. Air Quality Index · Dominant: O3
50 100 150 200

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

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
34 AQI 6.3 µg/m³
O3
Ground-level ozone
Dominant
35 AQI 38 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Mon 35 Good 35 34
Tue 36 Good 36 25
Wed 35 Good 35 28
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 dim. sept. 13, 19:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE2520 J/kg
MLCAPE1351 J/kg
MUCAPE2520 J/kg
SBCIN0 J/kg
MLCIN-26 J/kg
Lifted Index-4.8
Kinematics
0–6 km Shear11 kt
0–1 km Shear1 kt
Eff. Shear12 kt
0–1 km SRH3
0–3 km SRH21
Eff. SRH21
Storm Motion120° @ 17 kt
0–1 km EHI0.0
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index31.1
Thermo & Levels
PWAT1.61 in
0–3 km LR8.6 °C/km
700–500 LR5.8 °C/km
Total Totals46.5
LCL782 hPa
LFC984 hPa
EL145 hPa
Freezing Lvl16,220 ft