Based on satellite-derived snow depth (SD) over the Tibetan Plateau (TP), daily rainfall data from 261 meteorological stations in South China (SC), and the ERA-5 reanalysis dataset during 1979—2018, the relationships between TP winter snow depth and precipitation during the first rainy season (FRS) in SC are investigated in this study. The results show that: 1) The connections between SD over the western TP and precipitation during the FRS in SC are the most robust, and TP SD mainly affects frontal precipitation during the FSR, whereas it shows less impact on summer monsoonal rainfall. 2) The onset date of the FRS in above-normal TP snow years is about 20 days earlier than that in below-normal snow years, leading to more rainy days, a longer FRS, and more rainfall during the FRS. However, rainfall intensity during the FRS shows little difference between different types of TP snow years. 3) The TP is colder in an above-normal snow year, and the cooling effect stimulates abnormal anticyclonic circulation over the TP. However, tripole anomaly patterns of the 500 hPa geopotential height occur in the East Asian coastal region. The circulation configurations facilitate cold air invading SC in middle-high latitude regions, making SC colder. The enhanced northwest Pacific subtropical high intensifies the low-level southerly flow and water vapor supplement. The front swings northward-southward in northern SC during March and April. The FRS is established once the dry, cold, northerly flow and the warm, wet, southerly flow invade the SC in early April. In below-normal TP snow years, both the cold northerly and warm southerly flow are weak and inactive, and the front over northern SC is interrupted in early April. When the northerly and southerly flow invades the SC in mid-to-late April, the front is reverted and the FRS in the SC occurs later.