In recent years, destructive floods in South Baluchistan have caused many human and financial losses. The extremely heavy rainfall that have led to major floods in South Baluchistan occur under certain conditions. In this research, two case studies of widespread and severe floods in the southern region of Sistan and Baluchistan province in Dec 2020, and Apr 2024 have been investigated based on the data of provincial stations and Chabahar and Kanarak stations. The statistics recorded in the meteorological stations of Sistan and Baluchistan province show that Sistan and Baluchistan province has had unprecedented rainfall compared to the last 60 years. The statistical results of 24-hour heavy rainfall, based on the latest information received from 16 rain gauge stations, the amount of rainfall received in the province is reported to be more than 100 mm, which is equivalent to the rainfall of one agricultural year this year. Long-term in the statistical analysis section of the Q-Q charts, the observed values, histogram and probability density function related to the observed maximum show that the cumulative rainfall return period of 24, 48, 72, 96 and 120 hours are related to similar return periods. Events in consecutive years are short. The plot of P-P probability or theoretical probability versus the probability values obtained from the fitted probability cumulative function corresponding to each annual maximum observed cumulative rainfall also has an increasing trend. Based on these statistical results, in Chabahar station, the probability of rainfall is more than 40 mm in every 12 years, and the analysis results of Q-Q diagrams and P-P probability diagram in the catchment area of South Baluchistan also show that the probability of daily rainfall is 35 mm every ten years. And every hundred years the probability of rainfall about 50 mm in one day is not far from expected. The results of synoptic analysis in all cases indicate the existence of a low pressure system and a long trough in the upper levels of the atmosphere at the levels of 500, 300, 700 and 850 Hectopascal in the south of the province. The extreme gradient of temperature and wind speed along with vorticity fields are also clearly evident in the region. Heavy rainfall and torrential rain, momentary gusts, 10-degree drop in air temperature and night frost were among the most important phenomena that caught Sistan and Baluchistan province during floods