Heat wave

Down south for a couple of days and went out running at 6.45am, my first run since UK 70.3 .  Legs felt great but what's with the heat down here?  Sweat was pouring off me and it was early morning.  I had been reading up on heat training with Lanza in mind but wasn't expecting to find these temperatures in the UK.  So in the winter I'll be training indoors on a turbo trainer with the heating on or running outdoors with multiple layers on.  Should boost the sales of shower gel and deodorant!