I remember the lovely Pa. Summers from my two-year stint in Pottstown.
Similar to Phil, I have a fully perforated mesh jacket (Triumph Rochester), however it can still be pretty brutal down here. I always wear an open-face helmet for around town this time of year with sunglasses and perforated gloves. I'll try to keep that jacket on all Summer but no we'll have to see how it goes. A little run up to St. Augustine on A1A can be pretty hot in July!
Good luck, and ride safe!
Ryan