Do unseasonable temperatures like the recent mild spell have any effect on the next season?

Dear Tom,

Do unseasonable temperatures like the recent mild spell have any effect on the next season?

“Smiley” Mattesson
Chicago

Dear “Smiley”,
There was a time, before some of the driving forces behind seasonal weather (El Nino, for example) had been identified, that long-range forecasters relied heavily on season-to-season persistence — the assumption that an established weather trend would continue into the following season. It is now believed that one season’s extreme temperatures, like the recent warmth, do not necessarily lead to a continuation of that trend, nor to an opposite temperature extreme to maintain a balance. The latter might happen if we had an unchanging climate. It’s possible the weather would compensate for extremes. But climate is ever-changing. That renders short-term adjustments unlikely.