Vector-borne diseases (VBDs) represent a significant global public health challenge, with India hosting a diverse mosquito fauna of 3,583 species. In the arid and semi-arid landscapes of Rajasthan, shifting ecological dynamics have led to an increased prevalence of diseases such as Malaria, Dengue, and Chikungunya. This study aimed to assess the abundance and seasonal distribution of Anopheles, Culex, and Aedes mosquitoes in Railmagra, Rajsamand district, Rajasthan, and to correlate these findings with local disease trends and environmental drivers. A field survey was conducted from July 2025 to February 2026. Data were collected through larval and adult mosquito sampling in residential areas (330 houses) and aquatic habitats (ditches) using manual aspirators, light traps, and gravid traps. Morphological identification was performed to differentiate species, and epidemiological data were synthesized from the National Vector Borne Disease Control Programme (NVBDCP). Three primary genera were identified: Anopheles, Culex, and Aedes. A clear ecological succession was observed: Anopheles reached peak density during the post-monsoon period (September–October), correlating with 30 reported cases of Malaria. Conversely, Culex became the dominant genus during the winter months (January–February), peaking at 150 individuals in residential areas. Aedes populations remained lower but persistent throughout the study, linked to 20 reported cases of Dengue. Surveillance of ditches showed that breeding site availability dropped from 20 sites in the monsoon to 5 in the winter. The study highlights a strong correlation between seasonal environmental changes and mosquito population dynamics in Railmagra. The prevalence of these vectors, even in arid conditions, underscores the urgent need for continuous surveillance and integrated vector management. Recommendations include source reduction, the use of botanical larvicides (e.g., Neem oil), and physical barriers to mitigate the transmission of Malaria and Dengue in the region.