This is my backyard, a few days after a snow storm. The left side of the image is South. By the angles of the shadows from the tree, the clothesline, and the line support, you can see how far we are from the sun being directly overhead at noon (it gets closest at the Summer Solstice- as I said, this is the Spring Equinox).
That greenish patch to the left of the tree is where the sun has warmed and melted the snow and ice we've been chopping away at for the past few days.
Any structure that faces South and doesn't have anything in its way will get more sun and more heat during the Winter months, because the sun is angled so sharply from the South. This is reversed in the Southern Hemisphere!
This means, for example, if I built a low wall or cold frame on the right side of the lawn, it'd get lots of sun and not be shaded by the neighbor's fence, making it an ideal place to grow cool weather crops.
I wonder if my landlord would mind me building out there...