Abstract <p>The waste stockpiling before its incineration often leads to the production of substantial leachate. Climate might affect the leachate production and its treatment. Here, a systematic investigation of leachate quality and the operational status of leachate treatment stations in 9 incineration power plants from subtropical and temperate regions in China was carried out. The results indicated that the average annual leachate production rates of waste incineration power plants in both regions were 17%, with higher production amounts in summer and lower in winter. When compared to subtropical projects, those in temperate zones exhibited greater annual fluctuations in leachate production, poorer raw leachate water quality, and higher treatment loads during the summer. These characteristics posed higher operational management demands for the temperate leachate systems. The “pretreatment + biological treatment + membrane advanced treatment” system is the main technology for leachate treatment in waste incineration power plants. It could be found that the removal rates for chemical oxygen demand (COD), ammonia nitrogen (NH₃–N), and chloride ions (Cl^–) could reach 99.94, 99.88, and 95.70%, respectively. Meanwhile, the treated water met the reuse standards, proving the technology’s high efficiency and stability across different temperature zones. The average annual total operating cost of leachate treatment stations was approximately 50.62 yuan/t. Among the total cost, the electric cost accounted for about 50.95%, making it a key factor in cost reduction and efficiency improvement for leachate treatment systems. This study will provide valuable data and technical support for the efficient and economical leachate treatment in waste incineration power plants.</p>