Yes, the tours run in light rain and other moderate weather conditions. For winter time we have winter tires on segway so we can safely ride on snow. It is really safe, it is possible to play hokey on segway (but do not recommend to do it without an experience :). Check the link on YouTube.
In the event of severe or unsafe weather conditions [e.g. hard snow/ wet ice during winter months] the Segway tour may be canceled up to one hour before the departure time. In such cases customers will be offered the opportunity to reschedule for the next available tour.