Keep them cool and out of direct sunlight
The problem with a chinchilla being in direct sunlight is the heat factor. Chinchillas need to be kept at a temperature between about 65 – 75 degrees Fahrenheit and can have heat stroke if the temperature approaches 85 degrees Fahrenheit. If the cage were to sit in a sunny window for an extended period of time, it is likely that a chinchilla would become very uncomfortable from the heat and it could become a life-threatening situation.
If you’re ever in a situation where your chinchilla has gotten overheated, put an unopened soft drink (can or bottle) in the cage so the chinchilla can lay against it to lower it’s body temperature.
Many people think that a fan running in a hot room will cool off a chinchilla. That is not true. A fan only blows the hot air around and, since chinchillas can’t sweat, they will die just as quickly from overheating whether a fan is blowing or not.