As others have said, cotton kills in the cold, but it saves in the hot. So wear cotton undies (or no undies, going commando ain't all that bad in the heat), and I like BDU's. Tan will work, I don't like cammo either. Big pockets, tough, not all that expensive. A tan M-65 field jacket, with liner if you want, and a watch cap will help with the cold. During the day a wide brimmed hat, boonie or Tilley, and you are all set...