Natural Habitat
Cockatiels naturally hail from Australia, where they can live in areas that reach relatively high and low temperatures. At its coldest, a cockatiel's natural habitat can reach approximately 40 degrees Fahrenheit. At its warmest, it may be over 109 degrees Fahrenheit. These are extremes, however, and subjecting a pet bird to either such temperature -- especially for an extended period of time -- can result in unsafe and unsustainable body temperatures.
Safe Temperatures
A pet cockatiel should live in relatively consistent temperatures, as they are unable to adapt and regulate their body heat when environmental temperatures change. Ideally, a cockatiel's environment should be kept between 70 and 80 degrees Fahrenheit. While he can tolerate higher or lower temperatures, this is a comfortable medium for your bird that helps him maintain a healthy body temperature.
From thenest.com