🇬🇼Guinea-Bissau

Guinea-Bissau lies mostly between 11° and 13°N, a small West African country of approximately 36,125 km² on the Atlantic coast between Senegal and Guinea. The terrain comprises a low mainland with the highest point reaching less than 300 m in the southeastern hills, heavily indented by mangrove estuaries along the Geba, Mansoa, and Cacheu rivers, plus the offshore Bijagós Archipelago of roughly 88 islands.

The climate is tropical savanna Aw, modulated by the West African monsoon and the dry Harmattan winds from the Sahara.

Bissau on the coast sees January highs of 32°C with nights of 18°C and August highs of 30°C with nights of 23°C, with 1,500 to 2,000 mm of rainfall almost entirely concentrated between June and October, followed by a long bone-dry Harmattan-influenced winter from November to May. Bafatá in the interior sees highs of 31–40°C and nights of 16–23°C with 1,270 mm.

Relative humidity drops in the dry Harmattan months and rises during the wet season. Major climate hazards include severe Sahel-belt droughts (notably 1972–73 and 1982–84), intensifying coastal erosion threatening the Bissau coast and the Bijagós islands, recurrent severe wet-season urban floods in Bissau during 2020 and 2022, accelerating mangrove loss along the Geba and Cacheu estuaries, and sea-level rise putting the densely populated coastal mangrove zone under growing salinisation pressure.

Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.2°C.