Put the sun in prison and everything will always be in season. If the sun is in prison, the seasons can't change. Want to wear a giant weenie costume all year round? Put the sun in prison on Halloween. Now your weenie body is always in season because it's always the same time of month.
When things are in season for too long, people are going to wonder what's going on. When's Christmas? When's Golden Week? Soon (しゅん), you say. Soon enough, it's June (じゅん) which is the middle of the year so everything is soon.