Drought is an insidious climatic phenomenon that develops gradually when precipitation is significantly below normal values for an extended period—weeks, months, or even years—generating a cumulative water deficit affecting water supply, agriculture, ecosystems, and energy generation. Unlike other extreme weather events, drought has no abrupt onset or clear endpoint. Four types are distinguished: meteorological drought (precipitation deficit relative to the mean), agricultural (insufficient soil moisture for crops), hydrological (declining streamflows, reservoirs, and aquifers), and socioeconomic (when the water deficit affects economic activity and supply). In Mediterranean climates, interannual rainfall variability is naturally high, but climate change is intensifying drought episodes. Southern Europe is particularly vulnerable to drought: its position between the Azores High and African influence, combined with high evapotranspiration, creates structural water stress. The North Atlantic Oscillation in prolonged positive phase is one of the main triggers, diverting Atlantic storms to higher latitudes and leaving the Mediterranean dry.