If there is an auto supply store near you, you might want to spend a few dollars to buy some of the Meguiar's Auto wax. Mother's is another good brand.
Be sure to get the kind that is made for clear coat paints so it doesn't have any abrasives in it.
These auto waxes are excellent at resisting the effects of the weather be it sun, rain, fog or whatever. They will last far longer than Pledge furniture wax which isn't really up to the riggers of life outside.
I've had good results with Meguiar's Gold Class wax on both my Miata and my Royal Enfield.
http://www.meguiarsdirect.com/product_detail.do?q=4623