A motorcycle rider is heated by the steps of: transferring heat from atmosphere to a thermally conductive element mounted on a motorcycle by the Peltier effect; and circulating working liquid in a closed cycle from the thermally conductive element, through a garment worn by the motorcycle rider via an inlet coupling thereto and an outlet coupling therefrom, and then back to the thermally conductive element. In an alternative arrangement, a motorcycle rider is cooled by the steps of: circulating working liquid in a closed cycle through a garment worn by the rider via an outlet coupling therefrom, via a thermally conductive element mounted on the motorcycle, and then back to the an inlet coupling to the garment; and transferring heat from the thermally conductive element to atmosphere by the Peltier effect. In either case, both the inlet coupling and the outlet coupling are separable to allow the motorcycle rider to leave the motorcycle while still wearing the garment.