Diurnal variations of land surface temperature (LST) play vital role in a wide range of applications such as climate change assessment, land-atmosphere interactions, and heat-related health issues in urban regions. This study uses fifteen years (2003–2017) of daily observations of LST Collection 6 from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard the Aqua and the Terra satellites. A spline interpolation method is used to estimate half-hourly global LST from the MODIS measurements. A preliminary assessment of interpolated LST with hourly ground-based observations over selected stations of the North America shows bias and error of less than 1 K. Results suggest that the present interpolation method is capable in capturing the diurnal variations of LST reasonably well for different land cover types. The diurnal cycle of LST and time of occurrence of maximum temperature are computed from the spatially and temporally consistent interpolated diurnal LST data at a global scale. Regions with higher variability in the timing of maximum LST hours and diurnal amplitude are identified in this study. The global desert regions show generally small variability of monthly mean diurnal LST range, whereas larger areas of the global land exhibits rather higher variability in diurnal LST range during the study period. Moreover, the changes in diurnal temperature range for the study period are examined for distinct land cover types. Analysis of fifteen-year time series of diurnal LST record shows an overall decrease of 0.5 K in amplitude over the Northern hemisphere. However, the diurnal LST range shows variant changes in the Southern hemisphere.