Objectives: Doctors at the Ophtalmology Department, University Hospital of Split noticed an increase in rhegmatogenous retinal detachment incidence, especially in summer. The main goal is to investigate the frequency and possible periodicity of this condition during the year in order to determine whether the increase is real or just apparent. Subjects and methods: The data of 421 patients, i.e. 428 eyes treated for rhegmatogenous retinal detachment at the Ophtalmology Department, University Hospital of Split from the 1st January 2018 to 1st January 2024, were analised. Patients with both traumatic and non-traumatic RRD were included, while those with other types of retinal detachments and those with redetachments were excluded from the study. By inspecting the medical documentation, Data on the demographic characteristics of the subjects and the clinical characteristics of RRDs were obtained by searching through medical documentation. Both cumulative incidence and average annual incidence per 100,000 inhabitants of the Split-Dalmatia and Šibenik-Knin Counties were calculated, as well as the number of cases per season. Results: The incidence was increasing from year to year, except for 2019 and 2020. The average annual incidence per 100,000 inhabitants is 18.9 (95%CI: 18.5-19.2). A statistically significant difference in the number of RRDs during the seasons was proven, with the highest number in autumn and summer. Men were more affected than women and the right eye was affected more than the left, but these differences were proven as statistically insignificant. The largest number of patients belonged to the age group of 50 to 79 years. The majority of patients had only one rupture in the upper parts of the retina, the detachment mostly affected half of the surface of the retina, and macula was mostly lifted. Visual acuity was significantly worse in patients with macular involvement. Conclusion: The incidence of RRD is increasing and its periodicity is proven with the most frequent occurrence in autumn and summer. A smaller number of RRDs was recorded during the COVID-19 pandemic, but due to vitrectomy failure. RRD with raised macula is more common than RRD with still attached macula. The extent of detachment is bigger and the PVR grade is higher in patients with raised macula.