Natural fabrics are my natural preference, However the most extraordinary innovation has occurred from manufacturers, who evolved out of the professional mountain climbing community for example.
Outdoor clothing shops like   “Paddy Palin” or  “Kathmandu” have varying styles of clothing for different regions of the world and different climates, which although synthetic, in the main ,have amazing technical qualities for moderating body temperature,very clever fabric.The people behind these shops such as Tim McCartney-snape who along with Greg Mortimer,  who were the first Australians to reach the summit of Mount Everest..Macartney-Snape  also became the first person to walk and climb from sea level to the top of Mount Everest. it allowed him to.. by understanding the adversity in all these climatic regions to  cleverly help create fibres,that were comfortable for these,differing climatic regions,indeed, on Everest…life-saving fabric,s  that reduce sweat which can still occur in sub zero temperatures with exertion,  The body produces sweat to cool it, which is obviously not good in this situation…  so needs to be avoided. A good example that many people are now aware of is:Technology such as Gore-Tex, a  porous membrane Invented by
( Robert .W.Gore,) when the outside temperature is colder than the body temperature it creates a pumping action to remove sweat, but at the same time it’s porosity is too small for rain molecules to penetrate. Wool was used as a technical fibre, by people working in the outdoors, before synthetics were introduced,and football teams had wool Jerseys, one of the main features if they were wet, you would still stay cozy and warm, this is one advantage of the synthetics designed by the outdoor professionals that started these companies.

I live in a warmer climate and have found that it’s more comfortable to wear one of these leading brand synthetic T-shirts for example than a Gore-Tex raincoat in a warmer climate.
It is necessary for the outer temperature to be colder than your body temperature for Gore-Tex to work efficiently, to transfer the heat, in a warmer climate the temperatures probably roughly equal, and even though can be raining heavily I still feel cozy in the synthetic, as the Gore-Tex traps hot air against your body

It is interesting to see how high fashion has started to embrace this and action wear is  now seen on Paris catwalks and elsewhere, and embraced the  tenet as  in architecture: where form follows function.