n/a. The highest average temperature in Clearwater is August at 83.1 degrees. The coldest average temperature in Clearwater is February at 59.8 degrees. The most monthly precipitation in Clearwater occurs in January with 0 inches.The Clearwater weather information is based on the average of the previous 3-7 years of data.Loading...he Clearwater, FL pollution index is 93.8% less than the Florida average and 80.9% less than the national average.