Seasonal Forecast July-August-September 2026 (JAS-2026)

During the July-August-September (JAS) season, the Indian Ocean Basin is in its winter configuration. During this period, The Seychelles archipelago is predominantly influenced by southeasterly trade winds originating from the southern Indian Ocean subtropical high-pressure system, which advects relatively cool and dry air masses toward the region. Consequently, Seychelles generally experiences cooler temperatures, lower humidity, and reduced rainfall. Further, this season is associated with the northward expansion of the Southern Hemisphere subtropical high-pressure belt and the northward displacement of the Intertropical Convergence Zone (ITCZ). As the ITCZ moves away from Seychelles, the frequency of deep tropical convection decreases, contributing to generally drier and more stable atmospheric conditions over the islands.

The July-August-September (JAS) 2026 rainfall season generally indicates that Mahe, Praslin and La Dige are expected to experience near-normal to above-normal rainfall conditions during the season.

For July 2026, rainfall is expected to be near normal overall, although there is an increased likelihood of below-normal rainfall across Mahe, Praslin, and La Digue. Rainfall conditions are then expected to improve gradually during August and September 2026.