Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; We studied the influence of weather on the etiology of healthcare-associated bloodstream infections in a hospital in Brazil during the years 2005--2010. Monthly average temperatures were positively associated with higher incidence of gram-negative bacilli as a whole, Acinetobacter baumannii, and Enterobacter species. The same groups presented seasonal behavior in stochastic models.