A surprisingly popular search term is the phrase "summer penis". It's (largely) not from porn viewers who like their pornography a little sun-dappled, or obnoxious adverts asking if you are "summer penis ready", but because of an online rumor that your penis becomes larger in the summertime.

As numerous sites will tell you, during the summer months your penis may look a little bigger in comparison to the winter months due to a number of factors.

“When it’s cold outside, your body does try to maintain its internal heat, and therefore things may appear to be more contracted," urologist Jamin Brahmbhatt told Mel Magazine, in what is clearly a case for renaming it "not winter penis". 

"When it’s cold outside, blood vessels near the skin contract to maintain the internal heat," Brahmbhatt added. "However, this type of body heat regulation should not affect the overall size of your penis.”

He went on to suggest that in the summer months you may drink more water to remain hydrated, and your genitals may begin to look "bloated", which is not the sexiest word we've ever heard to describe genitals, giving the appearance that your penis is larger. 

However, this is all in relation to flaccid penises. In terms of erect penises, your penis could appear to be slightly larger because in warm environments blood vessels dilate more, allowing increased blood flow. So you may be more likely to fill your penis to full blood capacity during warmer months, but you are not increasing it beyond its maximum potential engorgement. Assuming you become engorged in a heated room during the winter, summer penis is not really a noticeable thing.

What is real, however, is summer penile syndrome. Summer penile syndrome is a condition that occurs mainly during the warmer summer months, and will certainly make your penis larger due to uncomfortable swelling.

The condition is also known as Lions Mane Penis, due to the unfortunate look produced by the swelling, which is like a donut (or lion's mane if you really squint) around the penis. 

The syndrome – largely seen in younger patients –  is usually caused by chigger bites on the penis, and sometimes exposure of the penis to poison ivy, sumac, and oak, usually after playing outside in wooded areas. The symptoms, which include a lot of itching, usually last for around 2 to 3 weeks, making it a real long-lasting summer penis.