Through years of integrated remediation efforts, the prevention and control of cyanobacterial blooms in Lake Dianchi have achieved remarkable interim progress. Since 2018, both the annual frequency of cyanobacterial blooms and the spatial extent of blooms have exhibited a sustained declining trend. However, a notable resurgence of cyanobacterial blooms was observed in 2023, drawing significant scientific and public attention. This study systematically analyzed the variation characteristics and outbreak mechanisms of cyanobacterial blooms in Lake Dianchi based on MODIS satellite imagery data (2018-2023) and integrated water quality and meteorological monitoring data. The monitoring data indicated that over the past six years, the annual frequency of cyanobacterial blooms in Lake Dianchi exhibited a "V"-shaped trend, with the value in 2023 (87.0%) being significantly higher than the six-year average (69.3%). The average cyanobacterial bloom area from 2022 to 2023 was markedly lower than that from 2018 to 2021. Specifically, the average cyanobacterial bloom area in 2023 (15.86 km2) was 65.3% lower than the six-year mean, though it showed an 11.4% increase compared to 2022. Spearman correlation analysis revealed that the frequency of cyanobacterial blooms and the average bloom area were significantly positively correlated with air temperature and precipitation but significantly negatively correlated with wind speed. Additionally, cyanobacterial density showed a significant positive correlation with total phosphorus. Multivariate linear regression analysis demonstrated that air temperature and wind speed were the key meteorological factors regulating cyanobacterial blooms in Lake Dianchi, whereas the explanatory power of total phosphorus concentration for variations in algal density was limited. Against the background of cyanobacterial density persistently exceeding the mild bloom threshold (1.0×10? cells/L) from 2018 to 2023, the rebound of cyanobacterial conditions in Lake Dianchi in 2023 was primarily driven by the synergistic regulation of meteorological factors. More specifically, during the non-bloom period (January-May and December), the increased proportion of 13-20°C temperatures accelerated cyanobacterial resurgence. In the bloom period (June-November), the higher frequency of low wind speeds (<2 m/s) facilitated cyanobacterial surfacing and aggregation, while the decreased proportion of temperatures below 13°C favored cyanobacterial proliferation. These combined factors likely contributed to the elevated incidence of algal blooms observed in 2023. Moreover, the significantly increased proportion of high temperatures (20–25°C) during the bloom period likely enhanced cyanobacterial buoyancy, serving as a key driver for the expansion of bloom coverage that year. The findings not only provide theoretical support for the daily prevention, prediction, and early warning of cyanobacterial blooms in Lake Dianchi, but also offer scientific references for managing cyanobacterial blooms in other plateau lakes in Yunnan Province.