<p>Precise and rapid evaluation of the temperature field in tripled-glazed insulating glass units (TIGUs) under intense solar radiation is crucial for the thermal-resistant design of glass curtain wall systems (GCWSs) and assessments of building thermal environments. However, available empirical data, traditional <i>T</i>_sol-air method, and numerical simulations are inadequate in accurately calculating the thermal behavior of this emerging energy-efficient building material, particularly for the complex heating effects of direct and diffuse solar radiation and the thermal convection of cavity gas in multilayer glazing systems. This study presents a comprehensive thermal analysis of TIGUs using a refined thermo-fluid-structure interaction (TFSI) finite element (FE) model that accounts for heat conduction, convection (both external and within cavities), and radiative transfer. The improved model, implemented in ANSYS and incorporating D-O radiation, <i>k</i>-epsilon (RNG) viscous, and energy models, demonstrates superior agreement with experimental results and the WINDOW software (MAPE = 2.45%), which addresses key limitations of existing standards and the <i>T</i>_sol-air method. A parametric study based on meteorological data from ten representative cities was conducted, identifying the influence of outdoor temperature, direct radiation, and diffuse radiation on the TIGU temperature field, with their effects quantitatively characterized by sensitivity coefficients <i>a</i>, <i>b</i>, and <i>C</i>. The concept of “peak region” was introduced to intuitively describe the non-monotonic thermal behavior under strong solar radiation. For the widely used configuration (6+12Air+6+12Air+6 mm), fitted equations were derived using least squares and Lagrange interpolation methods, with <i>R</i>² &gt; 0.99, enabling efficient estimation of temperature distributions under long-term climatic conditions.</p>