Read/published in late 70s or into 80s.

Hero is thrown into the story and begins in a grassland setting. Where the people are nomadic because of the slow planet rotation with grass fires causing them to move periodically.

He has to win clan acceptance and become their leader.

Then he moves on to some more stable settlements near the poles of the planet as they do not experience the fires, therefore have cities etc.

Seems like i remember the nomads were low tech, with the cities having higher tech. That is why this seemed more sci-fi than fantasy.

Cant remember much else, any ideas would be great. I have searched as much as possible by names, authors and titles and cant seem to find anything. Anyone?