In a warming climate, extreme heat has become more frequent and intense than ever before as the world grapple with its impacts on many socio-economic sectors, including health, water resource management, energy, and agriculture. However, there is a major gap in predicting heat waves due a lack of understanding of the mechanisms associated with them. This session aims to address all aspects of heat waves from both diagnostics and prediction perspectives. Oral and poster presentations are solicited on all topics related to heat waves worldwide, that address improved understanding of the mechanism and impacts associated with heat waves, predictability, and predictions at all time scales.