perforated/vented leather doesn't help much in real heat and humidity. i have this this
. jacket, which i really like, but not for the summer. i have this this
for the summer. may not be as safe, but it's safer than nothing. not sure if a vest would help, but you have to find something. would be safer to wear full leathers, but not when you're passing out from heat exhaustion and driving off a bridge or something.