I don't give it a thought if it is in the 90s but when the temps are in triple digits, I take it a bit easier. My worry is primarily about the heat silently eroding my judgement causing me to make a stupid mistake.

There is the argument that you need to go faster when it is hotter. The correct balance between the cooling effect of the increased wind vs. the heat generated by the effort could make this a valid argument. We've all noticed how hot it gets when we stop, right?