It is best never to keep a chinchilla outside as the weather could give it a shock and cause stress leading to illness and it is a prey animal(!), if you do want your chinchilla outside of the house you could get a properly build outbuilding with: Heating, lighting and opening windows for when it gets hot. But all of this is far, far to expensive! It is best just buying your cage and putting it in a room with (obviously heating and air con) and a noticeable different between light and dark, but not directly in front of a window! If your chinchilla is getting hot inside your house: open a window a little bit, make sure you have chinchilla granite cooling tile/s in the cage and if it is very hot put a couple of packs of frozen peas or ice cubes under the cage, (if you have a storage shelf under your cage put it there) and provide him/her/them with a nice cool bottle of fresh water.
All in all, don't bring your chin/s outside.
Tips by Jexhi5, hope your chins stay happy!