Minimum (Tmin), Maximum (Tmax), and Heatwave Thresholds in Celsius from 1980/1981 to 2022/2023 for 15 Focal Locations in Portugal

This dataset contains temperature and heatwave data for 15 focal locations across mainland Portugal, covering the period from 1980/1981 to 2022/2023. The data is derived from ERA5-Land reanalysis and includes minimum (Tmin) and maximum (Tmax) temperatures, as well as heatwave thresholds calculated using the Heatwave Magnitude Index (HWMI).The study investigates trends and characteristics of heatwaves in mainland Portugal, analysing three key annual parameters:Number of heatwave days (ANDH)Average temperature during heatwaves (AATW)Intensity of heatwave events (AIHD)Results reveal a consistent increase in heatwave persistence throughout mainland Portugal, with more pronounced trends for Tmax compared to Tmin. ANDH Tmin shows upward trends across all grid-points, with increases ranging from 0.8 to 4.2 days per decade. ANDH Tmax exhibits even more significant increases, with 11 out of 15 grid-points showing statistically significant rises, ranging from 2.2 to 4.4 days per decade. Coastal areas, particularly in the south, demonstrate the most substantial increases in heatwave persistence. This dataset provides valuable information for understanding the spatiotemporal patterns of heatwaves in Portugal and can be used for further climate research, urban planning, and public health initiatives.