The windows can get brittle in low temperatures, and they start to show wear and tear sooner if the Jeep stays outside in the winter. Heat is not much of an issue, as the Jeep heater is quite strong. Heated seats help if you have them. It will take a bit longer to warm up the interior space. By far the biggest issue is going to be that you don't have a rear wiper or defroster. Gets annoying after a few drives in wintry weather.