I'm a bit of a noob myself, but even in 100+ temps I'm usually fine for my 11-ish mile commute home as long as I drink a couple of sports-bottles-worth of fluid (I'm a gatorade *****) during the day.
Getting a wicking shirt made it nicer too.

Though, Tucson's humidity level is not exactly high most times, so it might be comparing apples to oranges for you East Coasters.

edit: wow, you can't say "who**" huh.