In tropical countries agriculture protected with passive and low-cost structures is one of the main alternatives for intensifying agricultural production in a sustainable manner. This type of greenhouses has adequate efficiency in cold weather conditions meanwhile its use in hot weather conditions presents disadvantages due to the generation of an inadequate microclimate for the growth and development of certain species. This has generated an important interest for the use of screen houses (SH) for the horticultural and fruit production, and currently there are many studies on the behavior of microclimates in SH; however, these experiments were developed for climatic conditions in other latitudes. In this research, a study was developed using a computational fluid dynamics (CFD) 3D numerical simulation, with the aim of evaluating the thermal and aerodynamic behavior of an SH under two specific configurations (under rain (RC) and under dry conditions (DC)). The CFD model was validated by taking experimental temperature data inside the SH. The results showed that: i) the CFD model has an acceptable capacity to predict the behavior of temperature and air flows, ii) simulations can be performed under environmental conditions of day and night, and iii) the RC configuration affected the positive thermal behavior, which limited the presence of the thermal inversion phenomenon under nocturnal conditions, meanwhile under RC daytime conditions, it reduced the velocity of the air flows generating higher thermal gradients compared to DC.