Most lemon trees will not survive in winter if left outdoors. They need to be brought indoors or placed in a protected area when the temperature starts to drop. Lemon trees can tolerate some cold, but they are not frost hardy. If the temperature dips below freezing, the tree will likely die. Some people try to overwinter their lemon tree by placing it in a garage or shed, but this is not ideal as these areas are often too dry for the tree. The best way to overwinter a lemon tree is to bring it indoors and keep it in a bright room with temperatures that stay above freezing.