The amount of heat required to increase the temperature of a substance by 1 degree Celsius is quantified as heat capacity, and this value determines how well a substance retains the heat.
Water has a relatively high heat capacity at 4.18 J/g*C, which means it takes more heat to warm a gram of water. This is why, throughout the course of a warm summer day, the water temperature in the ocean does not experience a significant change. And phenomena like land and sea breeze, dust storm, monsoon are possibly due to high specific heat capacity of water.