Religious affiliation in Nigeria is strongly related to ethnicity, with rather distinct regional divisions between ethnic groups. The northern states, dominated by the Hausa and Fulani groups, are predominantly Muslim while the southern ethnic groups have a large number of Christians. In the southwest, there is no predominant religion.
As in most of West Africa, Nigeria's climate is characterized by strong latitudinal zones, becoming progressively drier as one moves north from the coast. Rainfall is the key climatic variable, and there is a marked alternation of wet and dry seasons in most areas.