I always thought the faith of Islam proves in itself that Muhammad was pretty darn ignorant of the world outside Arabia. For example, the rule that all people must pray facing Mecca. The average Arabian would have a pretty easy time figuring this direction out, but now we have prayer mats with compasses built in to make sure you face the right direction, and even little tabletop computers specifically designed to not only point the exact direction to Mecca, but also time the five daily prayers in perfect conjunction with sunrise, noon, and sunset. If Muhammad (and Allah) had been aware of places such as, say, England in the seventh century, do you think that law would be put into place?
And there’s the issue of the pilgrimage. Every single Muslim on earth, with the financial means and physical strength, is supposed to take it. (Personally I don’t understand a god who insists his followers go on a specific pilgrimage and engage in specific rituals in that spot, but that’s just me.) This was fairly easy in the early days of Islam. Now we’ve got millions of people every year packing into Saudi Arabia, which has to resort to tents to accommodate all of them, and the mosque at Mecca constantly being expanded, and still has people pressed in at every side during pilgrimage time. Try to imagine a crowd of thousands of people circling a tiny building. The “run between two hills” has been reduced to a slow stroll because thousands of people running between two hills makes for a dangerous situation (could it be said then that modern Muslims aren’t conforming to Allah’s rules by walking?), and then there’s the well of Zamzam. When there were a few hundred or thousand believers, sure, getting water from the well was no real problem. Now we have lines in which people stand for hours on end to get a tiny sample of the water as it’s frantically bottled. (Also we have the issue of Allah making holy a well whose water is only questionably safe.) People get trampled every year throwing stones at the pillars. Obviously this was not an event meant to be perpetrated on such a large scale. Muhammad wanted his religion spread across the world - but to him, he was completely unaware of the world outside the peninsula.
Considering such facts it’s not hard to imagine Muhammad commanding a particular practice without any thought towards arctic regions and places where days could seasonally be longer.