Benin shares 2,123 km of land borders with Burkina Faso, Niger, Nigeria, and Togo. On July 12, 2005, the International Court of Justice of the United Nations defined the current border between Benin and Niger, following a dispute over islands in the Niger and Mékrou rivers: nine islands were awarded to Benin and sixteen, including Lété Island, to Niger. The coastline, along the Gulf of Benin – part of the larger Gulf of Guinea – extends over 121 km². The territory consists of a narrow strip of land oriented perpendicular to the coast, stretching from north to south for approximately 672 km. It reaches a width of 324 km at its widest point.
The climate is in the intertropical zone, generally hot and humid, with seasonal and geographical variations influenced by latitude, relief, and the alternation of seasons. Between 900 and 1,300 millimeters of rain falls annually, with the wettest regions located in the southeast, from Cotonou to Porto-Novo, the Atacora region between Natitingou and Djougou, and the Dassa and Ndali regions north of Parakou. The maximum rainfall occurs in the south (equatorial climate), from mid-March to mid-July.
The monsoon, oceanic and moisture-laden, blows from the southwest from April to November. The harmattan, a dry continental wind, blows in the opposite direction of the monsoon, from November to May, bringing orange ochre dust. The humidity level, which is always high, ranges between 65% and 95%. The average temperature is between 22°C and 34°C, with April and May being the hottest months.
