Designing buildings that can provide thermal comfort to their occupants in the current climate, yet can also adapt and continue to provide protection from unknown future changes in the exterior environment is currently one of the building industry’s greatest challenges. Building Energy Simulations use weather files, which then inform the selection of HVAC systems and other design decision. Despite being integral to decision-making, the most commonly used weather files describe climate conditions from 1959 – 1989: data that is over 25 years old. This White Paper aims to demonstrate why care must be taken to select weather files for energy modelling use that best describes the climatic conditions of a specific location, and which presents a method for using climate forecasting models in order to quantifiably estimate the potential outcome of climate change on a proposed building. See here to download the weather files.