[expat-in-the-uk]

Africa is in the southern hemisphere so it is summer at the end of December. Crops probably are being harvested at that time of the year.

[Verginius Rufus]

Actually more than half of the African continent is north of the equator, and the ancestors of most African Americans lived in the part of Africa north of the equator. True, the Swahili-speaking areas of East Africa are south of the equator.

There are some grain crops harvested in June in the northern hemisphere, so the same crops may be harvested in December in the southern hemisphere. Whether any of those crops were actually cultivated by agriculturalists in Africa south of the equator I don't know.