<p>In the foothills of the Eastern Himalayan region of India, the occurrence of the Southwest Monsoon brings significant seasonal variations in climatic parameters specifically precipitation (rainfall) and temperature, thereby, affecting the timing and duration of various stages of phenological events or phenophases of trees in the tropical semi-evergreen forests of this region. In this study, 10 different tree species were selected and data on 9 phenophases were collected for 2&#xa0;years, along with 4 climatic parameters to determine the associations between phenophases and climatic variables. The collected data was subjected to statistical analyses, specifically Spearman's rank correlation, Rayleigh's test and ridge regressions. Several vegetative phenophases—leaf initiation, leafing and leaf fall—have shown positive associations with the climatic variables. The application of Rayleigh’s test showed that leaf initiation (Z = 3.20, p = 0.04) and flowering (Z = 3.66, p = 0.02) exhibited seasonality. The ridge regression models of leaf initiation (R² = 0.73, adjusted R² = 0.69) and flowering (R² = 0.29, adjusted R² = 0.18) provide insights into the relationships between climatic variables and phenological patterns, revealing that leaf initiation is positively influenced by relative humidity and photosynthetically active radiation, while flowering is inversely affected by relative humidity. From this study, it is evident that the phenophases and climatic variables share convoluted relationships which is reflected in the occurrences of the phenophases specifically leaf initiation and flowering in the tropical semi-evergreen forest of the foothills of the Eastern Himalayan region.</p>