The surface urban heat island (SUHI) effect has garnered significant attention with the rapid urbanization worldwide. However, the primary factors influencing the spatial variation in SUHI intensity (SUHII) and the underlying mechanisms remain inadequately explored. This study investigated the spatial characteristics and influencing factors of SUHII in 626 counties across East China for the years (Grimm, et al., 2000), 2010, and 2020. Various methods, including urban–rural temperature comparisons, coefficient of variation, optimal parameter geographical detector, and regression analysis, were applied to land surface temperature data and 13 relevant influencing factors. The findings indicate that SUHII exhibited notable seasonal and diurnal variations. The daytime SUHII (SUHIId) in summer was the most intense, with an average regional value of 3.09 °C in 2020 and a peak of 11.74 °C in 2010. SUHII demonstrated a latitudinal gradient, increasing from north to south. The north–south difference in summer SUHIId was the largest, while the smallest variation was observed in winter nighttime SUHII (SUHIIn). The most significant factor affecting the spatial variation of SUHII was the difference in vegetation greenness between urban and rural areas (∆VG). Additionally, relative humidity (RH), precipitation (PRE), and air temperature (SAT) were crucial in shaping SUHII spatial patterns. These four factors exhibited highly significant positive correlations with daily mean SUHII (SUHIIm) across the study area, though the response of SUHIIm to each factor varied between northern and southern regions. Furthermore, surface albedo (SA) and population density (PD) significantly influenced SUHII, with enhanced interaction effects between factors. This study highlights the spatial distribution and variability of SUHII at the county scale under the influence of multiple factors. Urban heat mitigation strategies should prioritize increasing urban vegetation greenness (VG) and SA.
