Men are being advised to expect a warm-weather effect nicknamed ‘Summer penis’ as a major heatwave builds over parts of North America in the coming weeks.
The National Weather Service says roughly 120 million people could be affected as soaring temperatures arrive around the Fourth of July holiday period, with dangerously hot conditions forecast to affect large parts of the central and eastern US. Forecasters have warned that a heat dome is helping trap the heat in place, pushing daytime temperatures and humidity to uncomfortable and potentially dangerous levels.
Canada is also forecast to see unusually high readings, with parts of Ontario potentially reaching 99F, while several areas of Europe continue to deal with their own spell of extreme heat.
Alongside the standard advice about sunscreen, avoiding dehydration, wearing a hat and limiting sun exposure, doctors have pointed to another lesser-known effect that some men may notice in hotter conditions.
Forecasters say the intense temperatures are being driven by a heat dome, with the Midwest and the Mississippi Valley expected to bear the brunt first, according to the NWS.
The heat is then expected to spread toward the Ohio Valley and the East Coast over the weekend, where actual temperatures could sit between 95F and 105F, while humidity may push it to feel more like 100F to 115F.
Public health experts say that in very hot weather the body widens blood vessels near the skin to help release heat, and that can make some areas look a little fuller or more flushed. It is not the penis actually growing, but rather a temporary change in blood flow, hydration and tissue appearance. Heat can also make people feel more generally swollen or puffy, especially if they have been in the sun for long periods or have not had enough fluids.
Dr Chun Tang, a GP at private healthcare clinic Pall Mall Medical, explained what the term means and whether it should be a cause for concern.
Dr Tang told The Sun:
“So ‘summer penis’ is a term people use to describe when a male’s penis seems a bit bigger or fuller during hot weather.
“It’s not an official medical thing, just something people have noticed and talked about.”
He said the effect is linked to the way heat causes blood vessels to widen, which can alter how the area looks.
“The idea is that in warmer months, especially when it’s hot and humid, the heat causes your blood vessels to expand a bit, which can make things down there look a bit different. Some men notice that their penis looks a little larger, especially when it’s flaccid.”
Dr Tang added that increased blood flow can leave it feeling more relaxed or softer than usual during hot weather.
Dr Sarah Jarvis, GP and clinical director of Patient.info, has also addressed the topic in comments to The Sun, stressing that the penis is not actually growing, but may appear larger because of expanded blood vessels.
“Technically when you’re hot, as well as when you are excited, then your blood vessels may expand.
“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. It’s not going to make you perform better either – when you are erect your penis is swollen to the max anyway.”
To reduce the effect, Dr Tang recommended keeping cool, choosing looser clothing and making sure to drink enough fluids.
“Avoid too much heat, wear loose clothes, and stay well-hydrated. This can help minimise the effect.”
Doctors also say men should seek medical advice if any genital swelling is painful, persistent, associated with redness or discoloration, or happens alongside other signs of heat illness such as dizziness, confusion, nausea, severe headache or fainting. Heat exhaustion and heatstroke can become serious quickly in extreme temperatures, so it is important to move indoors, cool down and get help if symptoms worsen.