It's been up in the mid to low nineties over here, so not too bad. Soon it will be one-hundred plus, then at some point it will stop dropping below one-hundred in the evening. In July the Southwest monsoon weather comes and it is very humid and still above one-hundred. That is degrees in Fahrenheit, of course.

In my experience, it is one's shoes and kilt belt that cause a good deal of the heat problem when wearing the kilt here in the summer.

I have worn, with Jock's approval, a wide brim, straw hat with the traditional kilt.

With the contemporary canvas kilt, I have worn sandals.

I think I might be getting the shirt terminology mixed up; it sounds like some people are using the term T-shirt to mean undershirt. For example, I have some shirts that do not have the open button collar, like a polo shirt, just the round neck, and are not meant to be worn under another shirt. The sleeves are too long for them to be used as an undershirt etc.