Chester County, Pennsylvania, United States

Last updated: 1:14 AM CDT · Refresh

21°C

Feels like 22°

Overcast

▲ 30° / ▼ 20°

Wind

5 mph S

Humidity

96%

Dew Point

20°

Pressure

29.34 inHg

Visibility

9 mi

UV Index

0.0

Cloud Cover

88%

Sunrise

6:16 AM

Sunset

7:56 PM

Drag to pan · double-click to forecast a point

WeatherAI™ Analysis

WeatherAI Analysis: Chester County is currently overcast at 20°C. Precipitation is likely — peak probability 68% around 3 AM. Atmospheric instability is elevated (CAPE up to 1217 J/kg) — isolated convective development possible. Sunrise: 6:16AM · Sunset: 7:56PM.

45 AQI · Good Dominant: PM2.5 Air Quality

Hourly Forecast · Next 24 Hours

Now

21°

61%

3 AM

21°

67%

4 AM

21°

60%

5 AM

20°

23%

6 AM

21°

10%

7 AM

21°

8 AM

22°

9 AM

23°

20%

10 AM

24°

20%

11 AM

26°

32%

12 PM

27°

41%

1 PM

28°

47%

2 PM

29°

47%

3 PM

29°

48%

4 PM

29°

63%

5 PM

29°

45%

6 PM

28°

46%

7 PM

28°

37%

8 PM

27°

30%

9 PM

24°

30%

10 PM

24°

31%

11 PM

24°

21%

12 AM

23°

22%

1 AM

23°

7-Day Forecast

Today

30° 20°

Partly Cloudy with a 61% chance of rain.

Tue

29° 20°

Mostly Clear.

Wed

30° 18°

Mostly Clear.

Thu

28° 19°

Partly Cloudy with a 60% chance of rain.

Fri

27° 18°

Rain, 82% chance.

Sat

27° 19°

Rain, 82% chance.

Sun

28° 18°

Rain, 82% chance.

+ Feels like

TimeTempConditionsPrecipWindHumidity

Now 21° Overcast 61% 5 mph S 96%

3 AM 21° Overcast 67% 4 mph SSW 97%

4 AM 21° Overcast 60% 4 mph SSW 98%

5 AM 20° Overcast 23% 4 mph SW 98%

6 AM 21° Mostly Cloudy 10% 4 mph W 97%

7 AM 21° Partly Cloudy 4% 5 mph WNW 96%

8 AM 22° Mostly Clear 4% 6 mph WNW 94%

9 AM 23° Mostly Cloudy 20% 6 mph WNW 90%

10 AM 24° Partly Cloudy 20% 7 mph WNW 85%

11 AM 26° Partly Cloudy 32% 7 mph WNW 80%

12 PM 27° Mostly Cloudy 41% 7 mph WNW 75%

1 PM 28° Partly Cloudy 47% 8 mph WNW 71%

2 PM 29° Partly Cloudy 47% 7 mph WNW 68%

3 PM 29° Partly Cloudy 48% 7 mph WNW 67%

4 PM 29° Partly Cloudy 63% 8 mph W 67%

5 PM 29° Partly Cloudy 45% 8 mph W 68%

6 PM 28° Partly Cloudy 46% 7 mph W 72%

7 PM 28° Mostly Cloudy 37% 5 mph W 76%

8 PM 27° Mostly Cloudy 30% 4 mph WNW 80%

9 PM 24° Mostly Cloudy 30% 4 mph WNW 84%

10 PM 24° Mostly Cloudy 31% 4 mph WNW 87%

11 PM 24° Mostly Cloudy 21% 5 mph WNW 89%

12 AM 23° Partly Cloudy 22% 5 mph NW 89%

1 AM 23° Mostly Clear 9% 5 mph NW 90%

15-Day Forecast

Today

8/17

Partly Cloudy

61%

20°

30°

Tue

8/18

Mostly Clear

20°

29°

Wed

8/19

Mostly Clear

14%

18°

30°

Thu

8/20

Partly Cloudy

60%

19°

28°

Fri

8/21

Rain

82%

18°

27°

Sat

8/22

Rain

82%

19°

27°

Sun

8/23

Rain

82%

18°

28°

Mon

8/24

Drizzle

43%

15°

28°

Tue

8/25

Drizzle

44%

14°

28°

Wed

8/26

Drizzle

60%

17°

28°

Thu

8/27

Drizzle

60%

17°

28°

Fri

8/28

Drizzle

60%

17°

27°

Sat

8/29

Drizzle

60%

16°

27°

Sun

8/30

Drizzle

60%

16°

27°

Mon

8/31

Clear

60%

16°

27°

Good

U.S. Air Quality Index · Dominant: PM2.5

50 100 150 200

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

Pollutant Breakdown · Today

PM_2.5

Fine particulate matter

Dominant

45 AQI 8.1 µg/m³

O₃

Ground-level ozone

30 AQI 32 ppb

3-Day Outlook

DayAQICategoryO₃PM2.5

Today 45 Good 30 45

Tue 48 Good 39 48

Wed 55 Moderate 44 55

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. PM_2.5 (fine particles) is reported in µg/m³ and ozone (O₃) in ppb. Forecast source: NWS NAQFC.

Temp Dewpoint Parcel (SB) CAPE CIN Dry adiabat Moist adiabat Mixing ratio

RAP

Valid Mon Aug 17, 05:00'Z' · F0 · 130 (13 km CONUS/NA)

Hodograph · kt

0–1 1–3 3–6 6–9 km

Instability

SBCAPE0 J/kg

MLCAPE24 J/kg

MUCAPE125 J/kg

SBCIN—

MLCIN0 J/kg

Lifted Index2.6

Kinematics

0–6 km Shear20 kt

0–1 km Shear25 kt

Eff. Shear5 kt

0–1 km SRH155

0–3 km SRH162

Eff. SRH24

Storm Motion298° @ 21 kt

0–1 km EHI0.0

Composite Parameters

Sig. Tornado0.0

STP (eff)0.0

Supercell0.0

K-Index36.4

Thermo & Levels

PWAT2.29 in

0–3 km LR3.9 °C/km

700–500 LR5.3 °C/km

Total Totals43.4

LCL983 hPa

LFC—

EL—

Freezing Lvl15,039 ft

Chester County, Pennsylvania, United States

Alerts