Tropical and humid all year. Between November and April, it is very hot and dry, although the coastal areas are cooled by sea breezes. In December and January, the dry, dusty Harmattan wind blows from the Sahara. During the rainy season between May and November, rainfall can be torrential.

Sierra Leone is bordered to the northwest, north and northeast by Guinea Republic, and to the southeast by Liberia. To the south and southwest lies the Atlantic Ocean. A flat plain up to 110km (70 miles) wide stretches the length of the coast except for the Freetown peninsula, where the Sierra Lyoa Mountains rise to 1,000m (3,280ft). In some coastal areas, sand bars have formed that stretch out as far as 112km (70 miles). Behind the coastal plain is the central forested area, drained by eight principal rivers, which has been cleared for agriculture. The land rises in altitude eastwards to the Guinea Highlands, a high plateau with peaks rising to over 1,830m (6,000ft) in the Loma Mountains and Tingi Hills area. The Mende tribe is prominent in the southeast and the Temne in the western and northern areas.