A remote air conditioning start system includes a terminal of a user, a center server, and a vehicle that includes an air conditioner and is configured to communicate with the center server. The remote air conditioning start system includes first and second transmission units, first and second reception units, a start controller provided in the vehicle and configured to, when the second reception unit receives a start request, start the air conditioner, a determination unit provided in one of the terminal, the center server, and the vehicle and configured to determine necessity of defrosting of a window of the vehicle, and a notification unit provided in the terminal and configured to, when the determination unit determines that defrosting of the window is needed, notify the user that defrosting of the window is needed.