There’s something a little ironic about summer.
The sun is shining, it’s crazy hot out, vacation plans are coming together, patios are full… and yet you wake up with a sore throat, a runny nose, and that familiar feeling of “I think I’m coming down with something.”
Wait a second! Aren’t colds supposed to be a winter thing?
Not really. Contrary to popular belief, respiratory viruses don’t take the summer off. In fact, some of them circulate even more during the warmer months. That’s why so-called “summer colds” are very real.
In winter, colds are most often caused by rhinoviruses. In summer, enteroviruses tend to take over.
These viruses circulate more widely between June and October and can cause symptoms such as:
One interesting difference: unlike winter viruses, enteroviruses can also affect the digestive system. That’s why a summer cold can sometimes come with nausea, stomach pain or diarrhoea.
When temperatures rise, everyone looks for a bit of relief.
Shopping malls, offices, public transit, waiting rooms… these are often enclosed spaces that are crowded and air-conditioned.
As a result, even in the summer, conditions can still support virus transmission. Close contact in air-conditioned environments increases exposure, while dry indoor air can dry out the nose and throat—both of which play an important role in the body’s natural defense against germs. When those barriers are weakened, viruses spread more easily.
That’s why, even when it’s 30°C outside, indoor environments can sometimes resemble the conditions that help viruses circulate in winter.
Summer is also peak travel season. Airports, planes, hotels, train stations, tourist attractions; we’re constantly in contact with large numbers of people from different regions.
Every trip increases the chances of coming into contact with viruses our immune system hasn’t encountered before.
That’s also why some people get sick a few days after returning from vacation.
For many people, summer also means pollen, ragweed and other allergens.
Seasonal allergies often cause:
This ongoing inflammation can make the respiratory tract more vulnerable to viral infections.
In other words, allergies don’t cause colds, but they can sometimes make the airways more sensitive to viruses.
The same habits that protect us in winter also apply in summer.
A few simple tips:
The sun, holidays, and warm temperatures unfortunately don’t make viruses disappear. In most cases, symptoms clear up within a few days with rest, hydration, and a bit of patience.
When in doubt, BonsAi, Bonjour-santé’s AI health assistant, is available free anytime. It can help analyse symptoms, provide care advice, and, if needed, guide you toward booking an appointment with the right healthcare professional. That way, even when a virus shows up during your vacation, it’s easier to know what to do and when to seek care.
Are summer colds more contagious than winter colds?
How long does a summer cold last?
Can a summer cold be mistaken for seasonal allergies?
