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: 4:54 PM CDT  ·  Refresh
36°C
Feels like 38°
Clear
▲ 37°  /  ▼ 24°
Wind
12 mph S
Humidity
37%
Dew Point
20°
Pressure
29.07 inHg
Visibility
10 mi
UV Index
6.6
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 1739 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%
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
28°
3%
3 AM
27°
3%
4 AM
27°
3%
5 AM
24°
3%
6 AM
24°
3%
7 AM
25°
3%
8 AM
26°
3%
9 AM
28°
3%
10 AM
28°
3%
11 AM
31°
3%
12 PM
32°
3%
1 PM
34°
3%
2 PM
34°
3%
3 PM
35°
3%
7-Day Forecast
Today
37° 24°
Clear.
Mon
38° 24°
Clear.
Tue
39° 22°
Mostly Clear.
Wed
37° 23°
Mostly Clear.
Thu
36° 24°
Mostly Cloudy.
Fri
36° 23°
Clear.
Sat
36° 22°
Clear.
TimeTempConditionsPrecipWindHumidity
Now 36° Clear 3% 12 mph S 37%
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% 11 mph SSE 54%
11 PM 29° Clear 3% 11 mph SSE 57%
12 AM 28° Clear 3% 10 mph SSE 63%
1 AM 28° Clear 3% 10 mph S 68%
2 AM 28° Clear 3% 10 mph S 70%
3 AM 27° Clear 3% 9 mph S 74%
4 AM 27° Clear 3% 9 mph S 74%
5 AM 24° Clear 3% 9 mph S 75%
6 AM 24° Clear 3% 9 mph S 75%
7 AM 25° Clear 3% 10 mph SSW 72%
8 AM 26° Clear 3% 11 mph SSW 67%
9 AM 28° Clear 3% 11 mph SSW 64%
10 AM 28° Clear 3% 11 mph SSW 59%
11 AM 31° Clear 3% 11 mph SSW 54%
12 PM 32° Clear 3% 11 mph S 48%
1 PM 34° Clear 3% 11 mph S 47%
2 PM 34° Clear 3% 12 mph S 45%
3 PM 35° Clear 3% 13 mph S 44%
15-Day Forecast
Today
9/13
Clear
3%
24°
37°
Mon
9/14
Clear
3%
24°
38°
Tue
9/15
Mostly Clear
7%
22°
39°
Wed
9/16
Mostly Clear
7%
23°
37°
Thu
9/17
Mostly Cloudy
11%
24°
36°
Fri
9/18
Clear
6%
23°
36°
Sat
9/19
Clear
17%
22°
36°
Sun
9/20
Clear
43%
23°
34°
Mon
9/21
Drizzle
68%
22°
33°
Tue
9/22
Drizzle
68%
19°
33°
Wed
9/23
Drizzle
67%
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 Sun Sep 13, 20:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE1993 J/kg
MLCAPE323 J/kg
MUCAPE1993 J/kg
SBCIN-10 J/kg
MLCIN-182 J/kg
Lifted Index-3.9
Kinematics
0–6 km Shear11 kt
0–1 km Shear9 kt
Eff. Shear12 kt
0–1 km SRH-42
0–3 km SRH18
Eff. SRH18
Storm Motion112° @ 22 kt
0–1 km EHI-0.5
Composite Parameters
Sig. Tornado0.0
STP (eff)0.0
Supercell0.0
K-Index32.8
Thermo & Levels
PWAT1.53 in
0–3 km LR8.8 °C/km
700–500 LR5.3 °C/km
Total Totals44.3
LCL778 hPa
LFC754 hPa
EL156 hPa
Freezing Lvl16,266 ft