Usman, i like your observations & sincerely appreciate it.
We all have different points of observations to the common phenomenon even.
I can further elaborate it with following quotes which I like
"Beauty is always in the eyes of Viewer".
"Look the good in people and you will find good in them".
Just ignore what everyone says here. I know people feel rather easy to taunt rather than even trying to observe it. Speaking / writing is rather easier than being practical.
If a car is normally driven, when stop and open the bonnet and yes can feel a certain (lets call it standard) amount of heat.
But if car is bit over driven, using bad engine oil, running short water in radiator, etc. etc. then certainly the amount of heat will be more when we will open the bonnet. I fully agree with this and in anycase appreciate your point of observation.
Regardless of the weather (either in summer or winter), your observation is true.