Indeed all living apes are found in the tropics. The oldest known fossils from the human lineage (hominins) come from central and eastern Africa.
Comment: One must bear in mind that most human origins theories are not compatible with known fossils, and so the 'Out of Africa' theory for humanity remains just a theory, which however may be true for certain lineages, but not necessarily all.
The hominins who dispersed northwards into higher latitudes had to deal with, for the first time, freezing temperatures, shorter days that limited foraging time, snow that made hunting more difficult and icy wind chill that exacerbated heat loss from their bodies.
Comment: It's worth noting here that, as Pierre Lescaudron explicates in his article Of Flash Frozen Mammoths and Cosmic Catastrophes there's a variety of data showing that the climate on our planet has varied significantly over time, with just one example being that at least 15,000 years ago, and possibly even more recently, regions of Siberia appear to have been much more hospitable than they are today,: Mammoths survived in Siberia until just 3,900 years ago, climate change likely responsible for extinction, new study reveals
Given our limited adaptation to the cold, why is it that our species has come to dominate not only our warm ancestral lands but every part of the globe? The answer lies in our ability to developed intricate cultural solutions to the challenges of life.
Comment: See also: