The round wall directs wind around the structure and local people hang a heavy weight from the center of the yurt to give it resistance to the lifting force of the wind.
They are cool in the summer with the bottom edge of canvas rolled up to allow airflow. ( but also mosquitoes)and warm in the winter when a layer of thick wool felt is layered over the whole structure and covered with canvas. In the centre is a stove that can burn wood or dried animal dung.
They are very spacious.
You can tell the time by the sun shadow on the floor via the smoke hole in the centre.
BTW if you enter a yurt and in Mongolia don’t step on the door still it is rude.
If you sleep over don’t be shocked when members of the family take off clothes to change. Modesty is the responsibility of the viewer.