Why is there no summer in Nigeria?

Due to geographical location and climate, there is no summer in Nigeria. Nigeria is located at the latitude of 6 27' north latitude and belongs to the north of the equator, so it belongs to the tropical region. In the tropics, only between the Tropic of Cancer and the equator can there be four seasons: spring, summer, autumn and winter. Because Nigeria is north of the equator, there are only two seasons: dry season and rainy season. So there is no such thing as summer in Nigeria.