Although Nigeria lies wholly within the tropical zone, there are wide climatic variations in different regions of the country. Near the coast, the seasons are not sharply defined. Temperatures rarely exceed 32° C (90° F ), but humidity is very high and nights are hot. Inland, there are two distinct seasons: a wet season from April to October, with generally lower temperatures, and a dry season from November to March, with midday temperatures that surpass 38° C (100° F ) but relatively cool nights, dropping as low as 12° C (54° F ). On the Jos Plateau, temperatures are more moderate.
Average rainfall along the coast varies from about 180 cm (70 in) in the west to about 430 cm (170 in) in certain parts of the east. Inland, it decreases to around 130 cm (50 in) over most of central Nigeria and only 50 cm (20 in) in the extreme north.
Two principal wind currents affect Nigeria. The harmattan, from the northeast, is hot and dry and carries a reddish dust from the desert; it causes high temperatures during the day and cool nights. The southwest wind brings cloudy and rainy weather.