Enjoy your ride. I hope it's a safe one. Here are a few tips for cycling in hot weather.
I'll add one to that list: carry an extra water bottle that's extra cold - either partially frozen or with lots of ice in it. Wrap it in a towel and put it inside your pannier or rack pack to keep it cool. Pour some of the water over your head and shoulders from time to time to help cool you off during your ride.
Take care and stay cool.