trend analysis of humidex as a heat discomfort index using mann-kendall and sen’s slope estimator statistical tests

Background: the aim of this research was to assess the humidex (hd) trends as a thermal discomfort index by analyzing meteorological data during a 30 year period of summertime in iran.methods: for this purpose, data regarding average temperature and relative humidity were collected daily from 40 different synoptic meteorological stations during a 30-year statistical period (1985-2014). the hd index was calculated based on temperature and relative humidity according to an equation introduced by masterton and richardson. the mann-kendall and sen’s slope tests were performed to analyze the changing trend of the hd.results: based on the findings, in 72% of the meteorological stations, the hd followed an upward trend, so that 40% of them was statistically significant. the changing trends in temperature during summertime throughout the studied years fluctuated greatly but generally, in many regions such as the arid, semi-arid, and humid regions, this trend was mostly incremental. also, the changing trends in relative humidity in all regions was decremental throughout the years under study.conclusion: the changing trend of the hd, which is based on temperature and humidity, was incremental in arid and semi-arid regions and decremental in the mediterranean and humid regions.