http://en.wikipedia.org/wiki/List_of_North_American_deserts Which one are you going to?
All of my desert hiking has been in cargo pants, a t-shirt, a hat like pic related, and sunscreen. That's except for the first time when I didn't wear a hat, thinking my thick hair would protect the top of my head. Wrong.
It's a better idea to wear a long sleeve shirt, but I don't own one and can't be bothered.
http://www.rei.com/product/816463/rei-sahara-long-sleeve-t-shirt-mensLong sleeve, UV protection, moisture wicking, $30. Just don't run out of sunscreen.
