Abstract: First, the past 500 year data of grades of wetness is augmented for Guangzhou and shantou. Then, correlation and periodicity analyses are made with the continuous series and rainfall reports from Guangzhou and Shantou (88 and 108 years in Length, respectively) to estimate yearly and season rainfall (5 year running mean). Verification shows satisfactory fitness, statistic (average and variance) and periodic performance. The work is a preliminary attempt in reestablishing historic rainfall series for Guangdong.