Question: Is flirting more effective on sunny days?

Experiment: University of South Brittany researcher Nicolas Gueguen enlisted five 20-year-old straight male undergraduates as his experimental flirters. He selected them out of a pool of 18 volunteers, picking the ones that were rated most attractive by a group of 31 young women that studied their photographs. He instructed the men to approach young women on different streets in two towns near the Atlantic coast of France and ask for a phone number, using a standardized solicitation.

Meanwhile, test days were scored on a 9-point range of cloudy to sunny by two nonflirting assistants.

All in all, the five male volunteers approached 500 women on different days in late May and early June.

Results: The young men clearly had better luck on sunny days, with a 22.4 percent success rate among 241 women approached. On cloudy days during the study period, the flirters got a phone number just 13.9 percent of the time from 259 women approached.

If a woman gave her phone number to one of Gueguen’s compatriots, she was later phoned and told that she was a participant in a social behavior experiment, lest she wait by the phone in vain for her Prince Charming.

Takeaway: The average temperatures on sunny and cloudy days were about the same, so it’s very probable that the sun was the biggest impact on a lady’s receptiveness to flirtation. However, Gueguen acknowledges that there are other unaccounted-for weather factors that could subtly sway a woman’s receptiveness, like wind or humidity. The study also does not account for how many of the women approached were in relationships or what proportion were not attracted to men.

Courtship, more so than other social behaviors, may be more easily swayed by the condition of the sky. Gueguen noted that one previous study found that sunny days do not compel people to leave bigger tips at restaurants.

“It could be argued that women accepted the confederate's request more favorably on sunny days, because they were in a positive mood when solicited,” Gueguen wrote.

Gueguen has found that other environmental factors can give a boost of flirtation. In a previous study, he showed that women in shopping malls were more likely to give out their phone numbers if they were near areas with pleasant aromas, like pastries, than in areas with no odor at all. He has also found that romantic song lyrics can predispose a woman to be more receptive.

He’s also interested in exploring the flirting question from the other side.

“For example, are men in the street more likely to look at women around them or to approach women on sunny rather than cloudy days?” he pondered.

So, be en garde -- if you’re vacationing in France and an unspeakably gorgeous person solicits you out of the blue, you might have struck l’amour. Or you might end up getting a phone call from a laboratory.

Source: Gueguen, Nicolas. “Weather and courtship behavior: A quasi-experiment with the flirty sunshine.” Social Influence published online 2 January 2013.