The title is a question that is frequently asked of meteorologists, especially in the wake of an abnormally warm or cool season; it is a topic of interest among atmospheric scientists and the general public alike. In this article, we will attempt to answer this question using climatology, casting aside gut feelings and old wives’ tales.
Arguments for Yes (A Hotter-than-Normal Summer is Probable)
When looking at a potentially complex answer, it is important to look at the argument from both sides. With a fresh perspective, the reasoning for the answer will be more complete and justified. One justification for this argument is the continuation of an established trend. Record highs keep breaking and temperatures are above normal in much of the U.S. week after week. With such an established trend, why would it not continue ?
Along with this thought, many people will have a warming earth in the back of their mind. In that situation, it would reason that all seasons would be warmer. Because of this, it is reasonable to conclude that the summer ahead will be hotter than normal. Another argument is the shear extreme of this winter’s warmth. There is evidence to suggest that an extremely anomalous warm season can carry over into the coming seasons.
Thus, it is not really too surprising to run across statements from the general public suggesting that this warm winter of 2017 will carry over into the summer, resulting in hotter than normal temperatures.
Arguments For No (A Hotter-than-Normal Summer is Unlikely)
Weather patterns often repeat for weeks, months and even years. This can lead to periods of well below or well above normal temperatures and precipitation. These weather patterns can become locked into place for so long that it can feel like “a new normal” or a “new climatology”.
The weather pattern change is only temporary, though. Eventually, the weather pattern will change. If it changes in less than a few months then one abnormal season may not lead to another abnormal season. A warm winter may not lead to a hotter than normal summer.
A warm winter may not lead to a hotter than normal summer if a pattern change occurs. (e.g. change in the jet stream orientation). There are climatological teleconnections that are studied in order to get an idea of the future weather pattern.
The interactions of teleconnections is complex and becomes more unpredictable the longer the climatological forecast is in the future. A couple of more popular teleconnections that are studied include El Niño/La Niña including the Southern Oscillation Index (SOI) and the North Atlantic Oscillation (NAO).
A warmer than normal winter may be the result of the current climatological weather pattern. Since this pattern can change, a warmer than normal winter is no guarantee that the following summer will be hotter than normal.
Synthesis of Arguments and Conclusions
The logic that “a warm winter will lead to a hotter than normal summer” is an uncertain connection. Statistically, the odds for a “hotter than normal summer” are somewhat higher than a cooler than normal summer due to factors involved with a warming earth and long term persistent weather patterns.
In cases where the winter is extremely warmer than normal and cases where the winter patterns stay locked in place over multiple seasons, can lead to a situation where a hotter than normal summer follows a warmer than normal winter.
In no way is this guaranteed. The “this leads to that” argument in meteorology and climatology is much more complicated than a single cause-effect statement since there are so many variables at play. The complexity of variables (Butterfly Effect, Chaos Theory) leads to a much more complex situation than just “this warm winter will lead to a hotter than normal summer”.
It could be a hotter than normal summer, but not just because this is a warm winter. There are many factors that influence the temperature trends in a future season beyond what is currently experienced in another season.