Different investigations on seasonal variations of the pulmonary thromboembolism and deep vein thrombosis (DVT) incidence have not yielded a definite conclusion. Some papers showed significant increase in incidence of thromboembolism in winter; on the other hand, others neglected that correlation. Some articles have tried to show infrastructure of these variations. Better understanding of the cornerstone of these variations can result in prevention of disease and saving lives of susceptible people. In this narrative review article, we reviewed previous articles according to the region of study and tried to find the factors affecting diverse results among different studies.