<p>The planetary boundary layer height (BLH) governs the vertical transport of mass, momentum and moisture between the surface and the free atmosphere, and thus its characterization is recognized as crucial for air quality, weather and climate. Although reanalysis products can provide important insight into the global view of BLH in a seamless way, the in situ observed BLH on a global scale remains poorly understood due to the lack of high-resolution (1-s or 2-s) radiosonde measurements. The present study attempts to establish a near-global BLH climatology at synoptic times (0000 and 1200 UTC) and in the daytime using high-resolution radiosonde measurements over 300 radiosonde sites worldwide for the period 2012 to 2019, which is then compared against the BLHs obtained from four reanalysis datasets, including ERA-5, MERRA-2, JRA-55, and NCEP-2. The variations of BLH exhibit large spatial and temporal dependence, and as a result the BLH maxima are generally discerned over the regions such as Western United States and Western China, in which the balloon launch times mostly correspond to the afternoon. The diurnal variations of BLH are revealed with a peak at 1700 Local Solar Time (LST). The most promising reanalysis product is ERA-5, which underestimates BLH by around 130 m as compared to radiosondes. In addition, MERRA-2 is a well-established product and has an underestimation of around 160 m. JRA-55 and NCEP-2 might produce considerable additional uncertainties, with a much larger underestimation of up to 400 m. The largest bias in the reanalysis data appears over the Western United States and Western China and it might be attributed to the maximal BLH in the afternoon when the boundary layer has grown up. Statistical analyses further indicate that the biases of reanalysis BLH products are positively associated with orographic complexity, as well as the occurrence of static instability. To our best knowledge, this study presents the first near-global view of high-resolution radiosonde derived BLH and provides a quantitative assessment of the four frequently used reanalysis products.</p>