CLIMATE OVERVIEW. Piedmont, South Carolina, gets 48 inches of rain per year. The US average is 39. Snowfall is 2 inches. The average US city gets 26 inches of snow per year. The number of days with any measurable precipitation is 86. On average, there are 218 sunny days per year in Piedmont, South Carolina. The July high is around 90 degrees. The January low is 31. Sperling's comfort index for Piedmont is a 68 out of 100, where a higher score indicates a more comfortable year-around climate. The US average for the comfort index is 54.