Mice have a need to sleep in dark, temperate areas. If the space they are habiting becomes colder than 65 degrees, they will leave. Similarly, if the space gets hotter than 95 degrees, they will find other hotel accommodation.
Humidity is very hard on mice, so a high humidity over 65 percent, will be life threatening. Good ventilation is key to their survival, and they will perish if they are trapped in a space without fresh air. The mice will have skin issues as well, if the humidity drops below 25 percent. Some mice will be killed completely without temperate conditions.