The enclosure is not waterproof and to use it outdoors you must put it in a box or in other protected manner. There are several choices for a water-proof enclosure. For example, this one from amazon:
http://www.amazon.com/Orbit-57095-Sprinkler-Weather-Resistant-Outdoor-Mounted/dp/B000VYGMF2
is sufficiently large to fit the controller, transformer, and wifi adapter. You can also search ‘sprinkler enclosure’ or ‘sprinkler case’ to find other similar products.