I've used heavy nylon gaiters on my arms. They worked great. I think ARE sells something similar made for arms, but the ski gaiters were quite cheap and attached with velcro. Normally I wear a heavy lined denim long jacket in the cold and denim shirt and jeans otherwise. They are huge and in cold weather I use them as a top layer. It is sweltering in our hot humid summers, but not much choice as it seems accidents happen when least prepared. Oh, I also got chigger/mosquito/tick-proof socks last year that somehow protect my whole body from them. They are hot, but I think I can now wear slightly lighter clothing since the bugs can be atrocious and heavy clothing has been the best non-chemical defense.
