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United States › South Carolina › Charleston County › Climate Station CHARLESTON CITY, SC US Distance 1.5 mi Normals 1991–2020

30-year climate normals

Charleston County Climate and Weather Averages

Hottest month — July

87.5°

average daily high. The coldest month is January, averaging a low of 43.6°F.

Charleston County gets 44.26" of precipitation a year, and 37% of it falls in Jul, Aug, Sep.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

60° 80° JanFebMarAprMayJunJulAugSepOctNovDec
MonthAvg highAvg low Precip
January 58.0° 43.6° 2.56"
February 60.3° 46.1° 2.56"
March 65.6° 52.0° 3.03"
April 72.3° 59.7° 2.96"
May 79.0° 68.0° 2.58"
June 84.3° 74.2° 4.85"
July 87.5° 77.1° 5.08"
August 86.4° 76.5° 6.11"
September 82.6° 72.5° 5.25"
October 75.6° 63.2° 4.07"
November 67.1° 53.1° 2.30"
December 60.9° 46.8° 2.91"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 37% falling in the wettest three months (Jul, Aug, Sep).

January 2.56"
February 2.56"
March 3.03"
April 2.96"
May 2.58"
June 4.85"
July 5.08"
August 6.11"
September 5.25"
October 4.07"
November 2.30"
December 2.91"
Annual total 44.26"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 2,448
Heating degree days How much heating the climate demands 1,623
Approximate annual cooling cost At 16.18¢/kWh, South Carolina average $396
Approximate annual electric heating cost Lower where heating is gas rather than electric $92

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Charleston County, where electricity is one line of eight.

Common questions

What is the weather like in Charleston County?

Charleston County averages a high of 87.5°F in July and a low of 43.6°F in January. Annual precipitation is 44.26 inches, with essentially no snow.

When is the rainy season in Charleston County?

The wettest stretch is Jul, Aug, Sep, which accounts for 37% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Charleston County?

The average daily high in July, the hottest month, is 87.5°F. That drives 2,448 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Charleston County?

Effectively no. Measurable snowfall is rare in Charleston County.

Sources

  • Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station CHARLESTON CITY, SC US (USW00013782), 1.5 miles from the county centroid.
  • Heating and cooling degree days — NOAA, same station and period.
  • Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, South Carolina residential average.
  • Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.