I want to make a wooden mailbox that will be on a pole at the front of my house. I live in Phoenix Arizona so the temperature ranges where this will be sitting, are from 20F (-7C) to 150F (65C). (Remember this is sitting in the sun and stats measure the highs in the shade which is why the high appears way over what you would expect.) I doesn't rain often and when it does it usually buckets down.
I would love to ask the question "What wood, finish and joints should I use?" but I realize how subjective that question is. So instead I'll try and ask it in a more objective way.
If you were making a mailbox for these conditions what factors would you consider when selecting the wood, joints and finish?
I feel that an elimination answer is also perfectly acceptable. For example, listing wood, finish and joint types that would not endure these extremes would be helpful for myself and hopefully others reading the answers.