Water has a specific heat capacity of one calorie per gram degree Celsius. One calorie of heat energy is required to raise one gram of water one degree Celsius.
Water has a relatively high capacity to absorb and retain heat compared to other liquids, air and soil. Water molecules are strongly attracted to each other. So, some energy is used to overcome this attraction before the added heat energy causes a temperature change.
Since water absorbs and releases heat energy relatively slowly, water has a moderating effect on climate, and it also helps organisms regulate their body temperature. This high heat capacity causes a body of water to stay warmer or cooler longer than the surrounding earth and air.