This paper initially examines the geographical and geological conditions of the Persian Gulf region, referencing the geology of both the Oman and Persian Gulf basins across various periods, and addressing the underlying structure and formation of the islands. Subsequently, with a focus on the region's climate—particularly that of the Persian Gulf islands during different eras—and based on the Milankovitch theory, the paper considers orbital variations over time and the shifts in three influential climatic components: the Polar Vortex (PV), the Subtropical High Pressure (STHP), and the Intertropical Convergence Zone (ITCZ). It presents historical evidence of Iranian civilization, emphasizing the concentration of capitals near the Persian Gulf (Fars, Kerman, and Sistan), the attention of rulers towards the Persian Gulf, their settlement in the southern parts of the country, and their adaptation to the humid southern climate. In light of contemporary global warming, the paper concludes that the ITCZ has shifted from its normal position due to climate change and subtle alterations in the Earth's axial tilt. This shift has affected the southern region, which historically experienced distinct climatic conditions in terms of precipitation, as evidenced by features such as Hara (mangrove) forests, freshwater springs, and the evergreen farmlands of Abu Musa Island. The historical record of Iranian rulers settling in the region, along with the presence of colonial powers in the islands, underscores the significance of these unique climatic conditions, which provided human comfort. According to the Milankovitch climate cycle, this cycle is repeating after thousands of years, contributing to increasing rainfall in the southern coastal provinces of the country compared to previous years, with intermittent activity of the Sudan Low also being observed.