Summer ailment is a term used to describe illnesses that are more common during the summer months. Sunstroke, which has nine letters, is a form of heat stroke caused by overexposure to the sun and is characterized by dizziness, nausea, and confusion. Hayfever, which has eight letters, is an allergic reaction to pollen and other allergens in the air and is characterized by sneezing, itchy eyes, and a runny nose.