The Atlas of health and climate is a product of this unique collaboration between the meteorological and public health communities. It provides sound scientific information on the connections between weather and climate and major health challenges. These range from diseases of poverty to emergencies arising from extreme weather events and disease outbreaks. They also include environmental degradation, the increasing prevalence of noncommunicable diseases and the universal trend of demographic ageing. The Atlas conveys three key messages. First, climate affects the geographical and temporal distribution of large burdens of disease and poses important threats to health security, on time scales from hours to centuries. Second, the relationship between health and climate is influenced by many other types of vulnerability, including the physiology and behaviour of individuals, the environmental and socio-economic conditions of populations, and the coverage and effectiveness of health programmes. Third, climate information is now being used to protect health through risk reduction, preparedness and response over various spatial and temporal scales and in both affluent and developing countries. It is our hope that the Atlas of Health and Climate will serve as a visual - call to action - by illustrating not only the scale of challenges already confronting us - and certain to grow more acute - but also by demonstrating how we can work together to apply science and evidence to lessen the adverse impacts of weather and climate and to build more climate-resilient health systems and communities.