I'm not all that bothered by the heat when I'm riding.
Last year, the first 50 mile ride I did, which included the climb of the Bwlch, was a day when the temperature was 32C. Ok, I went through about 8 litres of water, but I neer really felt the heat was a major issue.
Today it was high 20's as I climbed Caerphilly mountain to go and watch the Tour of Britain (I climbed up the way they went down, but that is still a decent cat 3 on Strava), and it rally didn't bother me very much.
I'm also not as bothered as most people are by cold - I don't start putting arm warmers on until the temperature is down to about 10C, and the leg warmers don't come out until about 6ish, which is also about when I switch to the long sleeved jersey rather than just arm warmers..