I never thought of being a runner due to the Texas heat. Take today for example it is 100 degrees and humidity is around 94% feels like 107. I guess you really have to like running if you went for a 5k jog today. Maybe if I lived in the great north or east coast i would feel different.
Actually I love running in the heat. The other day it felt like 105 degrees here with the humidity and I ran 6 miles. The heat doesn't bother me one bit. When its 10 degrees out and my lungs are frozen now that bothers me.