Heatwaves cause mortality and morbidity worldwide. Critically, it contributes to various detrimental impacts on sustainable development, human safety, and the environment, but policymakers and the public pay little attention. During the heatwave period from 2015 to 2018, El Nio Southern Oscillation (ENSO) generated dry and warm temperatures in Thailand, leading to 158 deaths during the heatwave period. This study examines spatial and temporal heatwave variability (number, duration, frequency, magnitude, and amplitude). We also analyze the heatwave in urban, peri-urban, and rural Thailand. The result revealed that land surface temperature (LST) as a proxy for air temperature in heatwave assessment with a high correlation at r = 0.62 (HWN) and 0.71 (HWF) and a moderate relationship r = 0.48 (HWD), 0.39 (HWM), and 0.40 (HWA), respectively. It has been associated with heatwave occurrences far from the methodological station, especially duration and frequency. Northern Bangkok and Pathum Thani have the highest daytime and overnight heatwave intensities. Ultimately, our findings help decision-makers, and the public comprehends descriptive spatiotemporal heatwave trends, helping them to cope with extreme weather situations and contributing to future heatwave forecasts over Thailand's provinces.