Drought is one of the manifestations of climate change, which occurs in every region and country and expresses the deviation from average or normal conditions in the field of precipitation. The occurrence of drought is inevitable in both dry and wet regions, but with the dry and semi-arid climate of Iran, the probability of drought is higher and it is one of the natural phenomena related to meteorology and hydrology. Therefore, the aim of the current research is to investigate the curve of intensity, duration and frequency of meteorological drought in Malair plain of Hamedan province at an interval of 22 years (1994-2015). Meteorological data from the water year (1994-2015) for Namileh station was prepared from the Provincial Meteorological Organization and after sorting the precipitation data on an annual scale, it was used to calculate the SPI index. The results of this research showed that according to these results, Malair Plain has witnessed a sequence of droughts and droughts with different intensities during the studied period. So that in the water year of 1997-1998, the most severe drought occurred in this region with a value of -2.72, while in 2009-2010 this region had the most drought with a value of 1.97. Drought in this region had the highest frequency with 13 occurrences and occurred only in 9 dry periods, after severe droughts, there was no significant rainfall in the region. Based on the continuity of time, in the region two broad periods of four and five years drought occurred in 1996-2000 and 2010-2014, respectively, but drought periods were mainly two years. In the statistical period, it was found that the conditions of the occurrence of drought were associated with a downward trend and the occurrence of drought decreased to a negligible amount.
