It's all about the look. Seasons don’t have such an enormous practical impact on the surrounding world as weather conditions do, except for changing it on the visual matter. For instance, when winter approaches the Realm, there will be a lot of snow on the roof of your house. Besides, every climate zone has its own individual season style: continuous winter in the North and long, happy summertime in the South.
Here’s how it looks in Life is Feudal: