Living up here on The Moray Firth coast of North East Scotland, our climate can be quite harsh at times, and yes, even strong sunshine in the beautiful clear air.
I would agree with the sentiments already expressed on this thread. I'm a keen user of Autoglym products, both Super Resin Polish and High Definition Wax. However I know from previous threads on this forum, Autoglym products are not available on your side of The Atlantic, which is a shame. But I'm sure there are plenty of other products available that do just a good a job.
I also keep my car garaged as much as possible, not only to protect from the sun, but also to protect from seagulls, or sh*te-hawks as they are known locally !
Just keep it well waxed.