One heatwave, many definitions: Implications for global building performance analysis

Heatwave definitions vary widely across countries, yet their implications for building performance analysis remain poorly understood. This study reviews heatwave definitions from 25 countries, classifying them by meteorological parameters, threshold types (absolute, percentile-based, and hybrid), and duration criteria. The analysis reveals that 88% of definitions rely exclusively on air temperature, only 12% incorporate humidity, and required durations that trigger the heat event as a “heatwave” range from one to six consecutive days clustered at three and five days. This study proposes a classification framework that organizes these definitions into distinct pathways based on meteorological parameter, threshold method, and duration requirement. The variabilities in heatwave definitions can undermine cross-study comparability in thermal resilience evaluations, cooling energy demand assessments, and passive design strategy testing. To bridge global comparability with local relevance, this study recommends standardized humidity-inclusive reference heatwave scenarios for international benchmarking alongside region-specific criteria for local building code compliance and design optimization.