Although the Code allows MC, I will go along with where Greg is going regarding the patio/deck being rain tight.
Are you talking alum jacket MC, or steel jacket? Personally I would have an issue with alum jacket being 'outside'. Note I say 'personally'. Or are you talking PVC jacketed MC which would be no issues, with the listed connectors, and a suitable box for the enviornment.
Maybe PVC conduit and PVC device boxes would be a better choice?