It is July. It is HOT.
There is nothing you can do about it. You can only attempt to make peace with the heat. Accept it. Train in it and get acclimated. Do not hide from it, especially if you will be racing in the heat. Just be sure to adjust your pace expectations and hydration strategy. Here is a good article regarding heat training:
http://www.nytimes.com/2008/07/03/health/nutrition/03Best.html?ex=1372824000&en=6788a9a488df8d71&ei=5124&partner=permalink&exprod=permalink