Summer weather can present some challenges as you are enjoying the outdoors. One of the potential problems is dehydration. The human body is about two thirds water. Dehydration occurs when a person loses more water than they take in – by sweating for example. This can be a problem in the summer time, particularly in hot, windy weather when sweat might dry as quickly as it forms. Dehydration can lead to various heat related illnesses. Thirst serves as an indicator. But by the time you are thirsty, you might already be dehydrated. Easiest way to avoid problems is to drink lots of water – as much as 6 to 8 cups a day. Start drinking before you begin the activities such as hiking or playing ball and drink regularly, every twenty minutes or so.
Mary Knapp, Weather Data Library