While this theorem has its detractors, as the Post reporter acknowledged, there are many crime patterns relating to climate, temperature, seasonal variation and, consequently, to region and nation that have been persuasively established. However, the fact that such patterns have been shown to be quite consistent over extended periods of analysis does not completely resolve the issue of crime causation, although it lends itself to interesting lines of future research.

As the Post article notes, one of the earliest analysts of the connection between climate, temperature and aggression was the 19th century Belgian astronomer, mathematician, and statistician Adolphe de Quetelet (1796-1864). In 1835, Quetelet published a statistical analysis of reported crime in a number of European countries. He noted, among other things, that crime varies by season. Thus, Quetelet observed that many violent, interpersonal crimes show an increase during the hot months of the year.

Correspondingly, he found that many property crimes showed a tendency to increase during the colder months of the year in the countries he examined, including Belgium, France, and Holland. Quetelet characterized these patterns as constituting the “thermic law” of crime.

Extensions and variations of Quetelet’s observations have since become standard fare within conventional criminological circles. Thus, it is widely known within the United States that the incidence of certain types of crime varies by region. Interestingly, the regional variations correspond roughly to the climatic – temperature patterns discussed in the news article and discovered initially by Quetelet. The American south – the hottest and most humid part of our country for the longest periods each year – regularly produces the highest violent crime rates in the nation.

The west and especially the southwest, follow, with the east and, finally, the midwestern heartland, trailing. Internationally, one can discern some of the same climatic variations. Among those countries reporting the lowest violent crime rates over decades, even centuries, one may number: the United Kingdom, the Scandinavian countries (Sweden, Finland, Norway, and Denmark), Iceland and Greenland, Holland, and Quetelet’s own Belgium. Want to avoid violent interpersonal crime in North America? Nothing simpler: move to Canada. Hate to leave the U.S.? Choose Minnesota or North Dakota. Interestingly, however, American demographic patterns in recent years are just the opposite: Americans are leaving the east and north central states to move south and west. And what do they find? Certainly they are finding higher violent crime incidence, including the recent spate of “serial shootings” reported in Phoenix, Ariz.

While the patterns we are discussing are well established, it is dangerous and misleading to move from pattern recognition to causal analysis without a more finely nuanced understanding of all the factors that bear on different types of crime. Thus, while comparisons are difficult cross-culturally, there is no indication that mere climatic conditions are controlling with respect to a number of Muslim societies – most of which are located in equatorial or hot latitudes. Many Muslim countries in these regions report only moderate violence within their domestic society.

Yet, at the same time, many of these same societies report a rather high incidence of political violence, committed either by or against existing governments, including substantial contributions to trans-national terrorism and regional wars. In short, while climate, season and temperature have been shown to be highly related to the commission of certain types of crimes, this recognition is only a tantalizing lead inviting us to pursue more sophisticated analyses in the future.

Robert C. Hauhart is an associate professor of criminal justice at Saint Martin’s University, Lacey, Wash., and since 2002 has been teaching at the University of Maine at Machias.