Based on the daily precipitation, maximum temperature and MCI index data of 85 national meteorological observation stations in Guizhou Province from 1981 to 2010, and the daily precipitation of regional stations from April 2009 to August 2020, the thresholds of monitoring and evaluation indexes related to regional rainstorm, high temperature and drought were determined. The results show that: A day with 6 or more national stations (or 5 or more national stations and all stations with 6% or more) daily precipitation ≥50mm in Guizhou is considered as a regional rainstorm day. The percentage of sites ≥12% with daily maximum temperature ≥35℃ is a regional high temperature day. And the occurrence of 3 days or more is a regional high temperature process. A regional drought day was defined as one in which the percentage of sites with moderate or above intensity drought (MCI≤-1.0) was ≥12%. When the coincidence rate between a certain day and the previous day's regional drought site is ≥50%, and the duration is ≥15 days, a regional drought process begins. When the percentage of sites with moderate drought or above intensity for 5 consecutive days is less than 12% or the coincidence rate of sites with the previous drought day is less than 50%, the regional drought process ends. For monitoring and evaluation of regional processes of heavy rain, high temperature and drought in Guizhou province, the requirements of distance between adjacent stations and the coincidence rate of stations in high temperature processes ≥50% are no longer considered.