Objective: To investigate the correlation between an increased rate of juvenile myopia and seasonal variation in the Tangshan area. Methods: In this prospective study, 212 myopic juveniles (424 eyes) (age 8-16 years) were recruited from the Tangshan City Ophthalmology Hospital from March 20 to March 26, 2017. The refractive errors of the juveniles were recorded after cycloplegia, and monofocal glasses were prescribed. The same procedure was repeated September 23 to September 29, 2017 and March 21 to March 27, 2018. The changes in refractive error between summer and winter were compared using a paired t-test. Results: Myopia increased faster in the winter (0.46±0.12)D than in the summer (0.31±0.09)D,and the differences were significant (t=5.43, P=0.009). The same tendencies happened in juvenile males(t=4.36, P=0.013) and females (t=4.87, P=0.012), 8-10 years of age (t=2.31, P=0.042), 11-13 years of age (t=5.25, P=0.010), and 14-16 years of age (t=4.72, P=0.011). Conclusions: Myopia increase faster in the winter than in the summer in Tangshan area. We should pay more attention to the prevention and control of myopia in the winter half of the year in Tangshan.