Abstract:Based on the observation data of Henan Province during the winter half of the year from 1991 to 2020, the low temperature threshold, the process and duration of cryogenic freezing rain and snow are determined by mathematical statistics, and the meteorological indexes of each station are calculated and classified. The classification results are then subjected to spatio-temporal characteristic statistics and analysis of typical cases. The results show that the mountainous area of western Henan is a high incidence area of cryogenic freezing rain and snow, while the basins of southwestern Henan and northwestern Henan are the low incidence areas. The multi-year average frequency of the cryogenic freezing rain and snow at all sites is in descending trend from light to the heavy grade. The frequency and grade of cryogenic freezing rain and snow are not positively correlated with the latitude level, and extra-heavy events occur even more frequently at low-latitude sites than at high-latitude and mountain sites. In 2001, the number of cryogenic freezing rain and snow sites and frequencies was the most and the intensity was high, while in 2007, the number was the least and the intensity was mild. In 2018, the cryogenic freezing rain and snow was serious. January is the month to have the highest number of cryogenic freezing rain and snow sites and frequencies, followed by February. Temperature and precipitation are the key factors for the cryogenic freezing rain and snow. Low temperature and heavy precipitation are favorable for the occurrence of freezing weather. Temperature is the main factor affecting the frozen grade in the high altitude area while accumulated precipitation is the primary factor determining the frozen grade in the plain area. In addition, the location, intensity and moving speed of the weather system determine the hit area, grade and duration of cryogenic freezing rain and snow.