Winter in many parts of Canada and the US is an enormous problem for older people. We know that every winter there are many older people who do not get out of their houses for up to three months because they cannot move around safely in the snow, ice, or slushy conditions. This paper describes our efforts at the Toronto Rehabilitation Institute to address the difficulties faced by vulnerable people in winter. The first challenge comes from identifying their perceptions of problems caused by winter. We have subsequently studied the physiologic response to cold and outdoor walking behaviour in wintry conditions in order to understand the problems in greater depth and be able to develop solutions. Emphasis has also been given to investigation of the reported difficulty donning and doffing winter jackets and coats and the effectiveness and safety of winter footwear. Our continuing effort will be focused on the universal design of streetscapes, street furniture, winter clothing, footwear, and improved assistive mobility devices. We are also determining safe exposure levels to cold weather in order to inform the public of the risks associated with mobility in winter and to provide objective criteria for public agency responses to ensure safety and social interventions to reduce isolation in winter.