How much water to drink a day--in temperate countries--

So how much fluid does the average, healthy adult living in a temperate climate need? The U.S. National Academies of Sciences, Engineering, and Medicine determined that an adequate daily fluid intake is: About 15.5 cups (3.7 liters) of fluids a day for men. About 11.5 cups (2.7 liters) of fluids a day for women.