I wear a mesh jacket when it's very hot but it's not nearly as protective as my normal Frank Thomas jacket that I wear when it's 85 degrees or less. The mesh jacket seems like it has zero abrasion resistance and dubious impact resistance since the impact pads can move around a little. Better than nothing though. Better than a T-shirt. Also note that even mesh jackets can come with a removable inner liner; remove it to stay even cooler.
For pants, I wear normal textile motorcycle overpants, and underneath them shorts or even just underwear is comfortable when it's very hot. And boots, gloves, and helmet are always the same (unless it's very cold, then I use winter gloves).
You will sweat though, in anything. That's fine as the sweat will do a lot to keep you cool; just keep yourself hydrated.