Stuffing your manhood into a Speedo might take a little extra work, thanks to the phenomenon known as “Summer Penis.”
According to a number of medical professionals, the size of one’s manhood may actually appear to grow during the summer months, as temperatures outside climb. So, whether you like to show off or simply enjoy the view of a nice bulge, the time to hit up boy beach is now.
The term “Summer Penis” first gained popularity back in 2018, when writer Tracy Moore published a piece digging into the science behind it for Mel Magazine. Moore scoured Reddit and social media for summertime growers, before speaking with urologists about what’s really going on.
While one urologist said that one’s “penis size should remain the same” regardless of temperature, he explained that blood vessels may expand in the summer while regulating heat, giving the “perception that things are larger.”
A newer OUT report from July 2026 backs this claim, with license sexologist Sofie Roos telling the outlet that while “Summer Penis” is, in fact, a real thing, “the penis just looks bigger when being soft — you won’t get a bigger erection.”
Roos added that results are different for everyone, as it’s a “highly noticeable phenomenon” for some men, “while others barely see any difference — and both are fully normal.”
Sex expert Noah Heymann also explained to OUT that “Summer Penis” is basically the opposite of the also—unfortunately—real phenomenon “shrinkage,” where one’s junk appears smaller in the cold thanks to contracting penis muscles. So while that bulge may have a little extra oomf to it while laying out in the sun, you can still expect it to shrink right back up if you jump into the cold ocean.
That’s right: it’s very, very temporary—and is a reaction to certain temperatures, not the actual season or time of year.
“Summer penis is a fallacy, and there is no way to maintain larger flaccid penis size,” Heymann explained—while Roos added that there’s no way to keep it up, saying, “unless you’d like to go around with electrically heated boxers, you just have to appreciate the shrunken winter penis by remembering that it fulfills an important function.”
Speaking with The U.S. Sun in June 2026, Dr. Chun Tang confirmed “Summer Penis” isn’t “an official medical thing,” but instead “just something people have noticed and talked about.” Tang added that those who are typically sensitive to temperature changes are more likely to see the phenomenon come to life.
Another medical expert, however, warned that just because it may look like you’re packing more than usual, don’t expect it to affect performance in the bedroom.
“When blood vessels on the surface are a bit bigger, then things are going to look a bit bigger. But your penis is not growing, it’s just your blood vessels growing slightly larger as a way to reduce heat,” Dr. Sarah Jarvis told The Sun. “It’s not going to make you perform better either – when you are erect your penis is swollen to the max anyway.”
So enjoy these last weeks of summer—and take all those bulge photos for the apps now, while it’s still hot out there!
