: Drought is one of the costliest natural disaster and can cause devastating effects on societies and environment all over the world. In a general definition drought is a costly natural disaster which occurs when precipitation is less than expected or normal condition and the precipitation shortage continues for a season or more that could not provide human and environment needs. Drought is categorized into four Until now, numerous drought indices have been developed for describing and monitoring different types of drought and these indices have significant differences in their ability for detecting onset, persistence, and termination of drought. For example, several studies found that SPI, which is a meteorological drought index and is a function of precipitation, can detect drought onset earlier than other indices such as Palmer Drought Severity Index (PDSI) or Standardized Soil moisture Index (SSI). On the other hand, indices such as Standardized Relative Humidity Index (SRHI), Standardized air Temperature index (ST), and Standardized Vapor Pressure Deficit index (SVPD), which their inputs respectively are: relative humidity, air temperature, and vapor pressure deficit, at global and continental scales potentially detected drought onset earlier than SPI. One of the drawbacks of these indices is that they could not capture termination of drought like hydrologic or agriculture drought indices, because after the end of meteorological drought and start of rainfall, it may take several months until soil moisture or surface waters return to normal condition. The purpose of this study is evaluating and assessing the performance of SRHI, ST, and SVPD which are obtained from satellite data in drought early detection relative to SPI in Iran and within different climate Keywords: Drought early detection, multivariate indices, relative humidity, air temperature, vapor pressure deficit, and soil moisture
