While in Oz I wore a Joe Rocket mesh jacket. Was the whole of $35 from a clearout as newenough.com Couldn't recommend that enough. I'm not used to riding in really hot weather (just remember I live in the country of rain) and it made it bearable. Came with a shower/waterproof liner - not sure how good that was as I didn't test it. Also had a complete set of armour. And really was $35.
It's not hot enough for it here, but give global warming a chance...
Oh and it was a female one and fitted perfectly!
If you want a Triumph jacket that is good for warm weather and don't want a mesh one, try the Integra. Mine is just starting it's third summer.
Gina
03 America - Pretty stock - except the TBS wheel...

06 America - missing, presumed in bits. With it's TBS wheel...

09 America - It's very blue....