[17; 18] developed a two-dimensional model to investigate rain-wind-induced vibration in transmission lines and discussed the aerodynamic instability zone using the Lyapunov stability criterion. With the rapid progress of high-performance computation technique, numerical weather prediction (NWP) becomes an effective method to analyze wind-rain climates and meteorological variables [19]. The weather research and forecasting model (WRF) is one of the most widely used NWP systems designed for atmospheric research and operational weather forecasting. It is a state-of-the-art modeling system that simulates the dynamics and physics of the atmosphere to generate detailed weather forecasts and conduct meteorological research. WRF has gained popularity due to its flexibility, scalability, and ability to simulate a wide range of meteorological phenomena. The Advanced Research WRF (ARW) is one of the dynamical cores available within the WRF model based on a fully compressible set of atmospheric equations and is an appropriate model for simulating tropical cyclone systems. Many researchers have conducted typhoon-related studies based on the ARW model and found that the ARW model could reproduce atmospheric conditions and agree well with the measurements during typhoons [20; 21; 22; 23; 24]. The coupled phenomena of wind and rain is referred to as wind-driven rain (WDR), that is, raindrops carried obliquely by strong winds. It occurs when raindrops get horizontal velocity component from wind blows, rather than falling straight down vertically. Wind-driven rain can lead to water intrusion, moisture damage, and potential issues like leaks, rot, or mold growth, affecting the thermal and moisture performance of buildings [25]. Researches have been carried out to study the WDR on building facades with full-scale measurements [26; 27], semiempirical methods [28; 29], and numerical simulations. Although the numerical simulation of WDR with computational fluid dynamics (CFD) is complex and time-consuming, it can accurately determine the temporal and spatial distribution of WDR on complicated building facades, and the simulation accuracy has been validated with field measurements [30; 31; 32; 33; 34]. Most of the WDR researches focused on the amount of rainwater captured by building facades; however, the rain load caused by droplet impingement and water adherence cannot be neglected on large deformation structures like transmission conductors. The CFD model of WDR is a suitable tool to obtain the rain loading input of mechanical analysis of conductors since it provides the information of rain impact at droplet scale. In this paper, a multiscale numerical framework is developed based on the WRF-CFD and FEM methods to solve the WDR effects on the motion of a span of transmission lines located in Zhoushan Island. Compared to existing researches, the presented method enables the prediction of the dynamic responses of transmission lines under real weather conditions based on multiscale model coupling, and provides an insight into the wind-driven rain effect on conductors by means of multiphase CFD simulation. Section 2 proposes the methodology of the numerical simulation. Section 3 details the configurations of WRF model and presents the simulation results of Typhoon Lekima in 2019. Section 4 presents the CFD simulation based on the Eulerian multiphase (EM) model of the WDR flow field. Section 5 shows the finite element analysis of the transmission line under WDR condition. Section 6 provides discussion and conclusions.