Toronto is not as hot as LA and I am fortunate that my 7 mile commute is gently downhill all the way. I try to exercise a lot of discipline in coasting as much as possible on the way to work.
Polo shirts, if they are a knit fabric, are actually quite sweaty. I wear a short sleeved light cotton dress shirt and casual shorts on the bike, and I keep some long pants at work or roll them up and bring them with me and change at work. I might be slightly sweaty when I arrive on the hottest days, but no worse than if I had taken public transit. I have a fan in my office and use that when I arrive, before I start any face-to-face meetings.
It also helps not to drink coffee at home before commuting, or immediately after getting to work.
Last edited by cooker; 03-29-17 at 08:29 PM.