AbstractMediterranean Fruit Fly (medfly), Ceratitis capitata (Wiedemann), is considered to be one of the most destructive fruit insect pests throughout the world. In recent years, the temporal dynamics of the medfly have been extensively studied by season, and, to a lesser extent, on a daily basis. We exploited, for the first time, a sequential automatic medfly male trapping system, in combination with climate data, to characterize diel flight patterns of male medflies trapped. The process was carried out in four commercial citrus fields over three growing seasons. Results showed that throughout the year, medfly flight activity began 4–6 hr after sunrise and peaked up to 2 to 3 hr before sunset. Generalized additive models (GAM) of the 934 days sampled revealed that in the fall, the diurnal flight activity was unimodal, that is, it began increasing at noon, peaking in the afternoon. By contrast, in the spring and summer, the diurnal flight activity exhibited a bimodal pattern, decreasing at midday. GAMs also revealed that hour after sunrise and temperature influenced medfly captures, with the former the more dominant factor. Thus, photophase significantly impacted the medfly's diurnal flight activity in each season. This study demonstrated that automatic traps that timestamp each capture are a primary research tool in insect flight activity studies that contributes to understanding diurnal insect activity within the growing season.