NASA has determined global temperatures very precisely from the year 1884, with most of the world cold, but a noticeable hot spot in west Africa.
They only have data from one station in west Africa from 1884, and very little for most of the rest of the world
The one station they have from 1884 in west Africa is at Freetown, Sierra Leone.
You can see hot temperature in 1884, though they only have seven months of records from that year.
But how did they determine that the rest of Africa was cold?
Five independent groups came to the same precise conclusion as NASA.