Guinea pigs can live indoors and outside. However, the Humane Society recommends housing guinea pigs indoors. Guinea pigs should not be exposed to extreme weather conditions such wind, snow or rain.
Guinea pigs thrive in temperature controlled environments and should not be housed in humid, hot or overly cold temperatures. Ideally, guinea pigs should be housed in temperatures between 65 and 75 degrees Fahrenheit. According to The Small Animal Channel, guinea pigs can play outside as long as they are placed in a secure cage or pen. Avoid placing guinea pigs on damp grass or dirt because it can cause them to become chilled.