Drought refers to a lack of precipitation over an extended time period.
Droughts can be meteorological, agricultural, hydrological, or socioeconomical . Meteorological drought refers to dry conditions related to climate. Agricultural drought refers to factors related to irrigation and soil moisture. These are interconnected with precipitation, evapotranspiration, groundwater tables, and reservoir levels. Hydrological drought refers to a lack in water supplies, often evaluated at the watershed scale.