Angiostrongylus cantonensis is the major cause of human eosinophilic meningitis (angiostrongyliasis). Only few freshwater snail species transmit the rat lungworm A. cantonensis. However, apple snail (Pomacea spp.), introduced into China in 1981, has become the key intermediate host for A. cantonensis and drove the emergence of human angiostrongyliasis. Here we developed a biological model and assessed potential impacts of climate change on the distribution of Pomacea snails and hence the transmission of A. cantonensis. Mean January temperature and snail generation intensity were identified as the key factors determining Pomacea snails distribution. The generation intensity in the intermediate host, the longevity of A. cantonensis-infected rats and the dormant period of Pomacea snails were determined as key determinants of A. cantonensis transmission. The tight fit of our model predictions with data derived from a national sampling survey suggests that biological models hold promise for assessing potential impacts of climate change on infectious diseases once key determinants have been established. Geographical variation analysis may offer an approach to identify areas prone to the spread of vectors, intermediate hosts and parasites in a future warmer China and elsewhere.