As climate change increasingly interacts with socioeconomic development factors to contribute to migration, understanding how climate and migration can coalesce to exacerbate health risks is urgent. Our study examines how migration influences the health of Mekong Delta migrants in Ho Chi Minh City and explores the role of weather and climate variability in the migration experience and health status of migrants before and after migration. Using a qualitative approach, we conducted 43 in-depth semi-structured interviews. We found migration is a strategy to cope with livelihood insecurity in the Mekong Delta. Livelihood trade-offs in Ho Chi Minh City produce precarious living and working conditions contributing to changes in the self-reported health status of migrants after migration, while climate variability is a threat multiplier for migrants' health and livelihoods in both the Mekong Delta region and Ho Chi Minh City. Our findings illustrate the intersections of climate, migration and health where migrants make strategic health trade-offs to pursue better livelihoods, whilst weather and climate variability exacerbate the health risks and livelihood insecurity of migrants. This study supports the need to implement policies that reduce trade-offs, strengthen migrants' adaptive capacity, and address underlying socioeconomic and political factors shaping vulnerability across the rural-urban continuum.