We’ve often said that the IQ of a country is related to the temperature.
This is because in colder climates, people have to plan ahead to make sure they are going to be able to eat, so stupider people tend to die and not breed. In warmer climates, food is abundant all year around, so there is no real need to be super-smart in order to survive and reproduce. People in warmer areas were also not required to figure out complicated ways to keep from freezing to death.
We’ve now put together a chart comparing the average daily temperature of countries to their IQs. You will notice that in general, the higher the temperature, the lower the IQ. This is only not true in places like Singapore, where people from a Northern climate migrated in recent years to a Southern area.