Knowing the composition of mosquito community, their temporal dynamics and relationship with abiotic factors in urban areas is of interest in public health because many species are vectors of pathogens. This is the first survey of diurnal adult mosquitoes in an urban reserve in Buenos Aires City (Argentina). Fortnightly daytime samples were carried out during a year affected by a drought due to La Niña effect, to describe the adult mosquito community and analyze its association with environmental variables. Ten species belonging to the genera Culex L., Aedes Meigen, Psorophora Robineau-Desvoidy and Mansonia Blanchard were captured, some of which are vectors of pathogens (e.g. Aedes albifasciatus (Macquart) and the complex Culex pipiens L.). Diversity did not vary significantly among seasons, and the composition was moderately similar (ANOVA: p = 0.11; Dice-Sorensen: 0.50-0.77). However, classification of species as core, common or rare in the community varied. A canonical correspondence analysis allowed us to identify a group of five species associated with summer and high temperatures. The other species were not grouped, and were associated with rainfall, relative humidity or another season. These associations help to understand the presence and abundance of those species during a prolonged drought.