Although it is perforated, I wouldn't classify it as a 'summer' jacket unfortunately. I was always comfortable in it riding into the mid ~ upper 70's, but it doesn't really have the ventilation for the 80 ~ 90 degree days. That's pretty typical of most leather jackets though. On those days I would typically wear my Stage jacket which has a bit more perforation, unless I got roped into one of UP's mach retard pace rides, in which case I would wear this for the better armor and just be hot. Here's a sizing chart as a reference.