Abstract: Based on the manual observation hail data of Guizhou Province and ERA5 reanalysis data from 2011 to 2020, the spatiotemporal characteristics of spring hail processes in Guizhou were analyzed. Using the K-Means clustering method, hail processes were classified, and the corresponding weather conditions for different types of hail events were investigated. The results show that: (1) Spring (March to May) is the main period of hail occurrence in Guizhou (accounting for 89.3 % of cases). The spatial distribution of spring hail frequency generally shows higher values in the west and south, and lower values in the east and north. As the hail frequency increases, the spatial distribution gradually contracts toward the southwest. (2) The spring hail processes are mainly in a small local area (≤5 stations accounted for 62.9%). With the increase in the number of hail process stations, the frequency of hail process decreases rapidly. Among them, the large-scale hail processes are more likely to occur in early spring, and the small-scale hail processes are easy to appear in late spring. (3) The K-Means clustering results of spring hail processes in Guizhou are classified into 6 types, and Type II (east-west latitudinal to east-central type), Type IV (east-west latitudinal to west-central type) and Type V (north-northwest-south-southeast longitude to west type) are the main path types (accounting for 64.1%). All six types of hail processes predominantly occur between 17:00 and 20:00 (Beijing Time, same below), accounting for 53.5% of cases. The diurnal variation characteristics shows a typical bimodal structure, with the maximum and sub-maximum values appearing from 17:00 to 18:00 and from 19:00 to 20:00, respectively. (4) Before the hail processes (14:00—18:00), the thermal unstable stratification of the six key areas develops earlier than the dynamic instability, providing sufficient water vapor and strong updraft for hail formation. At the same time, the cloud water content in the middle troposphere increases above the 0°C level (about 600 hPa), and the cloud clusters can develop upward to around 500 hPa, providing material conditions for the formation and growth of ice particles.