Not OP, but where I am in the tropics it's quite common for everybody to go to bed at 8 or 8:30 and get up at 5. It gets dark at 5:45pm every day and light at 5:30am, so by getting up at 5 you optimize your daylight hours. Also it's cooler before the sun is fully blazing at 9:30am, so the early morning hours are best for jogging, outdoor errands, etc.