The main goal of this study is to analyze the influence of several environmental factors (temperature, precipitation, mode and duration of school transport, perception of physical activity [PA] opportunities, and perceived neighborhood walkability) on adolescent’s daily moderate to vigorous physical activity (MVPA) levels of two European mid-sized cities. Data were collected from a sample of 829 adolescents (49.7% Spanish; 55.2% females; 14.33 ± 0.73 years). Daily meteorological data were collected for the valid days for each subject and MVPA levels were assessed with Actigraph GT3X accelerometer during seven consecutive days. Data were analyzed using multilevel modeling. Warmer weather (p < .01), lower levels of precipitation (p < .05), and use of active school transport (p < .05) were significantly associated with higher MVPA levels. Environmental neighborhood perception did not show significant influence. Further efforts should be carried out to increase PA opportunities during colder periods, rainy days, and to promote the use of active transport