According to a new study published in the Journal of Building and Environment, researchers from Cardiff University, the University of Hong Kong, and Natural Resources Wales (NRW) have provided local authorities with new evidence on heat stress to consider when protecting people’s health from severe heat. The study predicts what it will feel like for people living in Cardiff, Newport, and Wrexham during future heatwaves. Results suggest that peak heat stress on people is expected to increase by 4.5C by 2080, especially for urban areas exposed to direct sunlight. The percentage of daytime hours without heat stress is expected to reduce significantly, from 30-80% in 2020 to 10–70% by 2080. To assess the extent of heat stress experienced by pedestrians, researchers created a ‘thermal digital twin’ of the urban centre of each city using innovative computer simulation, terrain data, building shapes, surface thermal properties and tree canopy cover. The paper concludes that preparing for extreme heat through mitigation measures, such as increasing urban green spaces, ponds, lakes, trees and artificial shading, is essential to reduce future heat stress in Welsh cities and towns.