In the present research, surface soil moisture (SSM) datasets at six subregions of Iran with different climate conditions were extracted from SMOSL3, ECV_SM ERA-Interim and ERA-Interim/Land SSM products.

Time series of averaged monthly mean SSM products and in situ ground precipitation and temperature measurements were derived for each subregion.

Correlation and trend analyses were conducted to aforementioned SSM datasets. Also, a drought analysis was performed based on time series of SSM.

All SSM datasets corresponded well with each other, and with observed precipitation and temperature.

Based on ERA-Interim and ERA-I/Land datasets, no trend was detected for the period 1980–1999 at all subregions. The Southeast region showed a significant negative trend for the period 2000–2014 based on ERA-Interim.