It seems the weather gets cold for a while and then it warms up again, or it gets way too dry for a while and then rains or snows a lot. Back, forth, up, down; weather is always changing from one side of average to the other. This can happen on a time scale of a few days, but it can also happen on a time scale of weeks, months, years, and longer. There is a general misconception that these ups and downs balance out over time, but they do not.
Long-term weather records show that weather is distinctly non-linear. Over short and long periods of time, such as days and weeks or decades and centuries, the warm spells do not completely balance out the cool spells. Likewise, the wet cycles do not balance out the droughts. This means that our concept of “average," particularly in the Northern Plains and Upper Midwest, is of limited usefulness.
