[whatisyour]

Spanish siesta's are still just 2-3 hours long. In traditional Indian cultures, people would often work between 6am and 11am and then from 5pm to 9pm, because middle of the day was too hot to do any kind of physical work.

So, I'm definitely going for weather as the reason for the tradition and not any timezone shift. And that also means that office work and air conditioning should reduce this practice over time.