YNOT – Adult industry entrepreneurs long have bemoaned the way business seems to slack off in the summer months. According to researchers at Villanova University, the phenomenon isn’t a figment of the industry’s imagination. Much like mating behaviors, pornography use may be seasonal.

The researchers studied Google Trends data for a range of porn- and prostitution-related search terms including “porn,” “xxx,” “x-rated” and a slew of more explicit words. What they discovered surprised them: Over the past five years, terms typically used to search for adult entertainment exhibited obvious peaks and valleys recurring in roughly six-month cycles.

A paper just published in the Archives of Sexual Behavior reveals porn’s peak season begins in late summer and lasts through winter.

Interestingly, dating search terms experience almost identical trends. Researchers said they could find no similar patterns among terms not related to sex.

In the offline world, cycles in births, sexually transmitted infections, condom sales and abortions roughly correlate with the cycles of porn, prostitution and dating, the researchers noted. They hypothesized humans may be biologically programmed to seek sex during specific seasons. Of course, they allowed, cycles in sexual behavior may be due — at least in part — to a relative lack of competition from other activities during colder months.