I live in SA but don't commute. You could commute year round but there will be times when you don't want to because of cold/wet/windy weather. I do know some people who do commute and the heat doesn't bother them. I run at lunch and you do get used to being in the heat (I'd hate to use the word acclimate but that is what happens). Mornings can be very warm, usually upper 70's to low 80's but the sun is low in the sky so that isn't a problem. But even at 6 pm, it can still be in the upper 90's to low 100's.
And yes, I also have a full sized pickup truck.