Creating state-of-the-art weather files to enable a climate-resilient built environment in the UK

CIBSE weather files are currently used by the building industry as the standard input data for building performance assessment for the purpose of regulatory compliance in the UK. In this study, the state-of-the-art CIBSE weather files are created with four major improvements incorporated, namely, (1) the enhanced representation of the UK climate through the creation of discriminative climate zones; (2) the latest climate change signals from the UK Climate Projection 2018 (UKCP18); (3) the satellite based solar radiation data from CAMS (Copernicus Atmosphere Monitoring Service) data repository; (4) the up-to-date observation record from 1994 to 2023. The methodology for creating the latest CIBSE weather files is elaborated in detail to enhance the transparency of the new weather data. Evaluated using a simulation case study, the new weather files demonstrate spatial and temporal coherency. The new future weather files enable robust building performance assessment against future climate conditions under different scenarios and will play an important role in designing climate-resilient buildings and delivering a net zero built environment. Practical applications As per the principle of “garbage in, garbage out”, weather data plays an instrumental role in streamlining building design to achieve both energy efficiency and thermal comfort. In this study, we present the methodology for the creation of the state-of-the-art CIBSE weather files. The new CIBSE weather files not only employ the update-to-date observation and projection data, but are also grounded on a total of 28 granular climate zones to account for diverse climate characteristics and eliminate the ambiguity with weather data selection. The new files will lay a solid data foundation for future-proofing building design in the UK.