In 2024, the Mediterranean Sea experienced more marine heatwave days than any other year in the past two decades, regardless of the detection method: a fixed baseline (1982–2011), a 20-year moving baseline, or detrended temperature data. The eastern Mediterranean also recorded the highest mean durations across all methods and mean intensities under the fixed baseline. Stating the baseline used is critical in marine heatwave studies, as it affects comparability and interpretation of results.