Safe temperatures for swimming pools vary with type of activity. According to the World Health Organization, water temperatures ranging from 78 to 86 degrees Fahrenheit are generally comfortable and safe for those engaging in moderate physical activity in a pool. However, if your child seems overly tired or the cold is accompanied by a fever, muscle aches or swollen glands, playing at home might be a better option than a trip to the pool. Generally swimming is fine with a light cold but if it is a heavy cold with lots of mucus it is best to stay home and rest.