On 21 and 22 November 2018, a group of experts in heat–health and heat–health action plans (HHAPs) convened in Bonn to discuss the possible revision of the HHAP guidance published in 2008 by the WHO Regional Office for Europe. They discussed preliminary findings from the evidence reviews that have been undertaken to inform a revised guidance, and they identified knowledge gaps where more evidence reviews or research is indicated. They also considered practical examples of HHAP development and implementation, as well as an example of heat warning notification system. Finally, they discussed a vision for a revised guidance, including the form it might take and the steps needed to develop it.