The climate of Saint Helena is tropical, marine and mild, tempered by the Benguela Current and trade winds that blow almost continuously. The climate varies noticeably across the island. Temperatures in Jamestown, on the north leeward shore, range between 21–28 °C (70–82 °F) in the summer (January to April) and 17–24 °C (63–75 °F) during the remainder of the year. The temperatures in the central areas are, on average, 5–6 °C (9.0–10.8 °F) lower. Jamestown also has a very low annual rainfall, while 750–1,000 mm (30–39 in) falls per year on the higher ground and the south coast, where it is also noticeably cloudier. There are weather recording stations in the Longwood and Blue Hill districts.

What current affects the environment of Saint Helena?