In India’s monsoon-dependent regions, variability in rainfall has emerged as an important climatic factor which heavily impact agricultural productivity. This study examines how agricultural productivity and seasonal rainfall variability relate to each other in West Bengal's Cooch Behar district, which is primarily an agrarian area in the sub-Himalayan plains. Based on secondary data which has been collected through official agricultural and meteorological sources, the study uses a descriptive and trend-based analytical methodology. The pre-monsoon, monsoon and post-monsoon are used to group rainfall data in order to analyze how they affect important crops like vegetables, paddy, jute, wheat, mustard, and maize. According to the results, crop productivity is highly affected by irregular rainfall distribution, delayed monsoon onset, intense rainfall, and dry spells, even though the district receives a comparatively high amount of rainfall annually. Paddy is found to be the most rainfall-sensitive crop, while other crops exhibit varying degrees of vulnerability depending on seasonal requirements and growth stages. Both excess and deficient rainfall contributes to production instability, increased cultivation costs, and income uncertainty for farmers. The study highlights the need for improved irrigation infrastructure, climate-resilient crop varieties, crop diversification, and strengthened flood management systems to ensure sustainable agricultural development in the district.