The 8- glass rule is inaccurate in general as well as for summer and is a myth for a few reasons. First, it leaves out the quantity per glass—it means to say 8-glasses of 8-ounces of water is enough—which is the “8 by 8rule.” Even the “8 by 8” rule however, is not supported by evidence. But it is easy to remember, which makes it ok to use but better stated as,  “8-glasses of 8-ounces of fluid (not just water) is the least amount you should drink a day.” Second, the amount of water you need to drink daily in summer or any season depends on several factors including:  
  • Your Health
  • Weight
  • How much you exercise
  • Where you live
  • What you wear especially when exercising
Putting the above facts aside, for the average adult living in a temperate climate, the Mayo Clinic says that The Institute of Medicine “determined that an adequate intake (AI) for men is roughly 3 liters (about 13 cups) of total beverages a day. The AI for women is 2.2 liters (about 9 cups) of total beverages a day.” This is a good rule of thumb to follow. Turning back to summer, the fact is we lose more water in heat because we sweat.  Sweating results in a considerable amount of water loss. Add a little exercise to the equation and you are looking an even greater fluid deficit. The problem is that if the lost fluids are not replaced, dehydration might occur and blood volume can decrease, which leads to a host of other cardiac issues. One key thing to keep in mind about proper hydration during summer is that every pound of body water lost due to sweating and especially aerobic exercise needs to be replenished (you can gauge the pounds lost during a workout by weighing yourself before and after exercise). To minimize water loss during the summer therefore, it is important to replace fluids while your sweating them out by taking small sips at regular intervals (whether during a walk in the streets or  during a workout).