I became a JW in Florida and I wore short-sleeve shirts with a tie and no jacket whenever it was hot. The brothers had no problem with it. I would conduct book studies w/o the jacket, and put it on if called upon at the KH to give a talk or handle a mic. I moved to Illinois and never changed. The elders knew that I was an elder before moving, so they never said anything. Many brothers were surprised (shocked is too strong) to see me get away with this. Apparently, the elders used to be very stuffy, the cong. got used to that, things never changed. So, many brothers started going out in service w/o a jacket, or taking it off at the hall more often. The elders never complained. They did have an unwritten "No braids" rule for sisters until an African sister with braids moved in and they decided not to counsel her, soon others were wearing braids.
My current cong. is very stiff about dress, but mostly just gossip and no real counsel. Since deciding to fade, but unknown to publishers, I have been able to put people in their place talking about Bible students in jeans or publishers going to the KH in various stages of casual. I really enjoyed telling them, SO WHAT? I started wearing khaki pants, with a shirt and tie, NO JACKET. As it gets cold, I will still do that, but carry a windbreaker or other non-suit jacket.