ECMWF’s 20th Workshop on HPC in Meteorology will be held in Bologna, Italy from 9 to 13 October 2023. The theme of the event is ‘Diversifying HPC’, reflecting the current trends in the field, such as the move away from large, monolithic computing systems and the growing use of graphics processing units (GPUs) in addition to central processing units (CPUs). The workshop will bring together experts in HPC from across national weather centres, academia, national supercomputing centres and industry to discuss the trends in hardware, such as from CPUs to GPUs, and from on-premises to cloud technologies, as well as changes in software.