average temperature for charleston sc
n/a. The highest average temperature in Charleston is June at 79.6 degrees. The coldest average temperature in Charleston is January at 49.7 degrees. The most monthly precipitation in Charleston occurs in January with 0 inches. The Charleston weather information is based on the average of the previous 3-7 years of data.he Charleston, SC air quality index is 2.1% less than the South Carolina average and 27.6% less than the national average.