<p>Temperate glaciers in the southeastern Tibetan Plateau have experienced significant mass loss and retreat in recent decades, yet detailed on-site observations remain limited. Here we present the measured records of surface mass balance, ice velocity and surface ice temperature of Baishui River Glacier No. 1 in Yulong Snow Mountain from 2018 to 2022. Our observations reveal an annual mean mass balance of −1.29±0.16 m w.e., demonstrating a significant seasonal imbalance between reduced accumulation (multi-year average of 0.51±0.07 m w.e.) and enhanced ablation (multi-year average of 1.80±0.26 m w.e.), which provides crucial evidence for explaining the long-term mass loss. The average annual ice velocity, predominantly controlled by monsoon season dynamics which contribute 69%–74% of the total movement, was measured at 26.91±2.76 m yr⁻¹ and exhibited a decreasing trend of 1.73 m yr⁻¹. The ice temperature fluctuated between −13.41°C to −0.04°C, with an average of −6.04°C. The ice temperature and air temperature synchronized well in the nonmonsoon period, while the temperature rise was not synchronized and slightly delayed in the monsoon period.</p>