Temperature is an important load on offshore wind turbine support structures, and environmental wind is the major factor affecting the structure’s temperature. This study focuses on offshore wind turbine support structures in oceanic wind environments. Specifically, it investigates the support tower, which experiences the most prominent temperature effects. Considering the influence of wind field local characteristic, a finite element (FE) calculation method for the structural temperature field is proposed. Initially, a FE transient analysis model of the temperature field for the wind turbine tower structure is established. Subsequently, the surface wind field of the wind turbine support tower structure in the marine environment is simulated and analysed to obtain wind speeds at various points on the tower surface under different incoming wind speeds. Following this, Type III thermal boundary conditions for heat exchange between the tower surface and the external environment are established based on local wind speeds. The FE transient thermal analysis method is then applied to calculate the temperature field of the wind turbine support tower structure. Finally, the temporal and spatial characteristics of the temperature field under different wind speeds are analysed and discussed through comparative analysis. By considering the local characteristics of the structural wind field, consistent with actual engineering situations, the time-varying temperature field of the structure can be calculated more accurately, which provides a key theoretical basis and technical support for the design of offshore wind turbine support structures, service state identification, and safety management.