I have a suspicion that most if not all rain gear will allow some moisture to develop. So keeping that in mind I picked up a cheap rain jacket from Performance Bike that lists at about $20 on sale a month ago for about $ 16. I had it out today on a 5 hour ride (admittedly at a sedate pace ), at the end of which, I was fairly dry. The jacket is vented under the arms, and I kept the velcro closure in front opened about 50 % for ventilation as well. Todays weather was around 45 degrees a with light rain falling all of the time.