Salinity refers to the concentration of dissolved salts in ocean water, usually expressed in parts per thousand (‰). It is not uniform across the world’s oceans and varies both spatially and temporally due to the interplay of several physical and climatic factors. One of the most important factors affecting ocean salinity is evaporation. In regions where evaporation rates are high, such as the subtropical high-pressure belts, water is lost to the atmosphere while salts remain behind, leading to higher salinity. This is evident in areas like the Red Sea and the Mediterranean Sea, where intense evaporation and limited freshwater input result in elevated salinity levels. Precipitation is another key factor influencing salinity. In equatorial regions, where rainfall is abundant throughout the year, large volumes of freshwater dilute the salt concentration in surface waters, resulting in lower salinity. Thus, there is a general inverse relationship between precipitation and salinity. Similarly, regions experiencing seasonal monsoons also show fluctuations in salinity due to varying rainfall patterns. The inflow of freshwater from rivers plays