A statistical analysis of significant wave height (Hs) in a location offshore Portugal continental coast, Leixões, is performed. The spectral and parametric information of sea states at this point used in this analysis was obtained from a 21-year hindcast simulation using the spectral wave model simulating wave nearshore (SWAN) forced by wind fields produced by the Weather Research and Forecasting (WRF) model forced by the ERA-Interim reanalysis. The modeling of the climatic variability of directional spectra provides information of the shape of the expected directional spectra in the various sea states at these locations, i.e., how the spectral parameters and their probability of occurrence change in the regions studied. The occurrences of spectral classes are estimated, and for each class, the variability of the spectral parameters is described by means of joint distributions. The classification of the different sea states provides important information about the wave conditions present in the target areas. A relation between the sea states and the Lamb weather types (WTs) as well as a methodology for classifying atmospheric circulation patterns is presented in this study. The results of this study provide a description of the wave climate through demonstration of the interaction between sea states and weather patterns and relating different circulation patterns to different sea states. This study provides useful information on the wave conditions that can be utilized in the design of ocean engineering structures as well as in the assessment of the operability and safety of shipping and renewable energy devices.