The Brain’s to Blame (Sort Of)
Exposure to sunlight prompts the brain to produce more serotonin, the neurotransmitter associated with elevated mood. When we have extra serotonin, we feel more positive, satisfied, energetic, and have higher self-esteem. (In the winter, the lack of sunlight and serotonin are what contribute to seasonal affective disorder.)
Since the days are longer and most people spend more time outdoors, summertime is prime serotonin time. We are, to some extent, a whole lot happier in the summer. And that general air of positivity makes us feel better about ourselves, and more likely to approach an attractive stranger or pursue a relationship. When we are feeling good about ourselves, we have fewer inhibitions. Not to mention that some studies have shown that testosterone levels in both men and women peak during the summertime. Testosterone is the hormone that’s closely associated with sex drive—the more of it you have, the more sex you want. So in those respects, our brains are literally signaling us to feel energetic, optimistic, and horny in hot weather.
Context Counts, Too
But beyond hormone fluctuations, summer itself also creates both opportunity and desire for more carefree behavior. Countless studies show that when we’re on vacation, we feel freer, more daring, and less inhibited. We do things that we wouldn’t do in our everyday lives. For anyone in school, summer is quite literally a three-month vacation, but even for those long out of college, summer offers many of the hallmarks of an extended holiday. In the summer we tend to work fewer hours, stay out later, drink more alcohol, attend more parties, and encounter more opportunities for socializing and hooking up. From movies to music to fashion trends, pop culture creates the expectation that even responsible adults should treat summer as one long party. The fact that summer encourages everyone to bare their beach bodies in revealing clothing doesn’t hurt, either.
Eventually, fall comes back, the days get shorter and cooler, we return to our normal lives, and we re-evaluate. Is it any wonder that it starts to become apparent that the itinerant pan-flute player who seemed so amazing on those sultry, tequila-soaked August evenings starts to look like a less-than-desirable long-term mate? Autumn is so good at snapping us back to reality. But oh, those summer nights…