Summer is when the polyester come into its own JK, especially the 'wicking' weaves, but you need to wear it under something with mesh panels or light goretex, for evaporation which is what actually cools you down. A few times last summer I wore a long-sleeve poly top under just the fox armour (which is mesh constructed) and was nice and cool even on hottest days as it evaporated sweat very well and the breeze from riding even felt frigid at times. But I never felt properly protected and went back to cotton under leather, lifting my leg up to force a breeze up the trousers a few times. The smell? Well I just rinsed it all (because it was very dusty too) and hung it over a line, it was dry next day. Take two on a trip and swap around? My niece rides road trips a lot, on an Aprilia with full perforated leathers and BMW designed summer under-garments and says it is cool and comfortable. She says decent helmet ventilation does a lot as it cools the head, she was a paramedic and has seen it all and so she has spent out on the best gear all round.