The urban heat island (UHI) effect will persist for a long time and influence human health, energy consumption, and future urban planning. Understanding the cooling effect of water bodies and green spaces can help alleviate the frequency of extreme climate, especially during torridity seasons. In this study, correlation and regression analysis were used to measure the relationship between land surface temperature (LST) or cooling indicators and landscape factors. In addition, the cooling intensity, distance, and threshold value of efficiency (TVoE) of water bodies and green spaces were detected. The results confirmed that: first, the cooling effect of water bodies were stronger than that of vegetation in most cases and more water bodies’ layout in the region was advocated; second, increasing vegetation coverage within 27% of the region can effectively and economically alleviate the thermal environment; and third, the green samples with an area of 0.57 ha and a high vegetation index had a higher cost performance ratio. The results provided quantitative guidance for urban public service spatial planning of water bodies and green spaces to prevent the continuous increase of urban background temperature.

The deterioration of the urban thermal environment has seriously affected the quality of life of urban residents, and studying the optimal cooling landscape combination and configuration based on local climate zones (LCZs) is crucial for mitigating the thermal environment. In this study, the LCZ system was combined to analyze the spatial and temporal changes to the thermal environment in the central area of Fuzhou, and the 159 blocks in the core area were selected to derive the optimal LCZ combination and configuration. The conclusions are as follows: (1) From 2013 to 2021, the building layout of the study area became more open and the building height gradually increased. The high-temperature areas were mainly clustered in the core area; (2) The LSTs for low-rise buildings (LCZ 3 (41.67 °C), LCZ 7 (40.10 °C), LCZ 8 (42.61 °C), and LCZ 10 (41.85 °C)) were higher than the LSTs for high-rise buildings (LCZ 1 (38.58 °C) and LCZ 4 (38.50 °C)); (3) The thermal contribution index for low building types was higher for dense buildings (LCZ 3 (0.4331), LCZ 8 (0.3149), and LCZ 10 (0.2325)) than for open buildings (LCZ 6 (0.0247) and LCZ 9 (0.0317)); (4) Blocks with an average LST of 36 °C had the most cost-effective cooling, and the combination and configuration of LCZs within such blocks were optimal. Our results can be used to better guide urban planners in managing LCZ combinations and configurations within blocks (the smallest planning unit) at an earlier phase of thermal environment design, and for appropriately adapting existing block layouts, providing a new perspective on urban thermal environment research with important implications for climate-friendly city and neighborhood planning.