Chester County

30 Year Climate Normals (Chester 1NW*, 1SE)
Max Temp. Mean Temp. Min Temp. Precip CDD HDD
1971-2000* 72.2 F 60.1 F 48.0 F 47.87 Inches 1558 3326
1981-2010 72.5 F 60.4 F 48.3 F 45.75 Inches 1670 3342
1991-2020 72.1 F 60.4 F 48.8 F 45.92 Inches 1668 3302

Temperature Records (1923-2020)


Highest Maximum: 106 F, August 21, 1983; Chester 1 SE
Lowest Minimum: -5 F, December 13, 1962; Chester 1 SE

Precipitation Records (1922-2020)


Highest Daily Rainfall (COOP): 8.4 Inches, August 23, 1967; Chester 1 SE
Highest Daily Rainfall (CoCoRaHS): 5.42 Inches, August 27, 2008; Lowrys 3.6 ENE
Annual Average Rainfall: 46.25 Inches
Wettest Year: 1964, 64.63 Inches; Chester 1 SE
Driest Year: 1999, 19.81 inches; Great Falls
Highest Daily Snowfall: 8.3 inches, January 11, 2011; Lowrys 3.6 ENE (CoCoRaHS)

Severe Weather Events- Countywide

Tornado

15 Tornadoes (1950-2020)
  • E/F0: 4
  • E/F1: 9
  • E/F2: 2
  • E/F3: 0
  • E/F4: 0
    • Period Of Record: 1950-2020
    Strongest: F2 on April 16, 1994 and EF2 on May 5, 2020
    Longest Path: 1.39 miles on November 16, 2011
    Widest Path: 100 yards on November 16, 2011
    1 tornado related fatality
    4 tornado related injuries
    Total Damage Costs: $7.6 Million

    Thunderstorm, High, and Strong Wind Events

    143 Total Wind Events (winds exceeding 50 knots or 58 miles per hour, 1955-2020)
  • 139 Thunderstorm wind events
  • 4 High wind events
  • 0 Strong wind events
    • 0 Wind-related fatalities
    0 Wind-related injuries
    Total Damage Costs: $261,000

    Hail (>1.0 inch)


    47 Hail events (1955-2020)

    Lightning


    1 Lightning event (1993-2020)
    1 Lightning related fatality
    0 Lightning related injuries
    Total Damage Costs: $0

    Flood

    13 Total Flood Events (1993-2020)
  • 6 Flood Events
  • 0 Coastal Flood Events
  • 7 Flash Flood Events
    • 0 Flood-related fatalities
    1 Flood-related injury
    Total Damage Costs: $l45,000

    Winter Weather-Related Events

    46 Total Winter Weather-Related Events
  • 4 Winter storm events
  • 5 Ice storm events
  • 10 Heavy snow events
  • 2 Frost/freeze events
  • 21 Winter weather events
  • 4 Cold/wind chill events
    • 0 Winter weather-related fatalities
    0 Winter weather-related injuries
    Total Damage Costs: $57.130 Million