Sao Tome and Principe Weather

Sao Tome and Principe climate

Sao Tome and Principe is a small island nation in the Gulf of Guinea, straddling the equator approximately 250 kilometers off the coast of Central Africa. The two volcanic islands have a tropical wet climate with a pronounced dry season called the Gravana from June to September, when cooler, drier air from the south brings relief from the otherwise persistent heat and humidity. Annual rainfall varies dramatically with altitude and aspect, from about 1,000mm in the drier northeast lowlands to an extraordinary 7,000mm on the southwestern mountain slopes.

The islands sit in one of the most convectively active regions of the Atlantic, with frequent thunderstorms building over the warm Gulf of Guinea waters. Pico de Sao Tome, the highest point at 2,024 meters, creates its own weather system, with clouds forming around the peak almost daily and heavy orographic rainfall feeding streams and waterfalls down the densely forested slopes. Despite their equatorial location, the islands are south of the main Atlantic hurricane belt and rarely experience tropical cyclones.

Sao Tome city on the northeast coast has a tropical climate with average temperatures around 26°C year-round and moderate rainfall of about 1,000mm, much of it falling from October to May. The southwestern coast is one of the wettest inhabited areas in the tropics, receiving relentless rainfall outside the Gravana season. Principe, the smaller northern island, is slightly wetter overall than Sao Tome. The surrounding ocean waters are consistently warm at 26-29°C, and the equatorial doldrums bring calm winds for extended periods, occasionally broken by intense squall lines.