Green infrastructure-based heat mitigation strategies can help alleviate the overheating burden on urban residents. While the cooling effect of parks has been explored in individual satellite-based studies, a global, multi-year investigation has been lacking. This study provides a comprehensive global assessment of the daytime surface park cool island (SPCI) climatology, using land surface temperatures from 2,083 systematically selected parks worldwide (2013–2022). Through detailed park selection and data stratification, the key drivers influencing the observed SPCI intensity are isolated. The analysis reveals that cooling is strongly linked to park type, with well-treed parks being, on average, 3.4°C, cooler than the surrounding urban area during summer. It is further investigated how SPCI is influenced by seasonal variations, droughts, and urban morphology across diverse background climates. These findings, along with the developed global SPCI data set, offer critical insights for designing climate-resilient green spaces.