Can a Change in Weather Make You Sick?

Staying healthy in every time zone and hemisphere

Traveling from small-town Texas to Amsterdam is a cultural shock, but could it actually be a shock to your immune system, too? If you grew up with parents who insisted that wearing a sweater could keep you from catching a cold, you may suspect that changing temperatures can make you sick. But like so many old wives' tale, the idea that fluctuating weather causes illness is only sort of true. If you always get sick when you travel to a place with different weather than you have at home, it's probably because you're exposed to new viruses and bacteria in a new place, not because of the weather itself.

Q: Does cold weather cause sickness?

A: In a word, no. But there's good reason that people tend to get sick at the beginning of autumn and winter. Cold air doesn't cause illness, but germs flourish, and the human immune system is weaker at cooler temperatures, according to researchers at Yale.

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People also tend to catch viral illnesses in cold weather because the conditions drive people indoors, and a lot of people sharing close quarters leads to sickness. One sick person who touches several doorknobs in restaurants, hotels and shops leaves germs behind for the next person to pick up and spread further. When people spend most of the day outside, they have less opportunity to pass germs back and forth.

Q: I always get sick on vacation. Why is that?

A: It's always possible to catch a cold when you travel to a cold place. But what about when you travel to the beach, or to another warm-weather locale?

Any change in environment can make you feel unwell because different places have different allergens that your body isn't used to fighting. If your immune system is weakened by certain diseases, medications and lifestyle habits (like smoking, poor nutrition and poor sleep), you may be more susceptible to getting sick when you arrive in a new city.

Of course, there are other reasons people get sick while traveling. For instance, intestinal issues caused by bacteria are common, often the result of eating in restaurants that don't follow good hygiene practices. This affliction is most common in Africa, Asia, the Middle East, Mexico, Central America and South America, according to the CDC, and less likely in the U.S., Canada and most parts of Western Europe.

Q: How can I avoid getting sick while traveling?

A: The bottom line is this: different areas have different allergens and viruses. So if you get sick when traveling, it's often related more to the fact that you're in a different place than that you're in different weather. But no one wants to spend vacation sniffling in bed or stuck in urgent care. Wash your hands frequently with warm soapy water while traveling, and be mindful not to touch your face after touching germy surfaces, like the tray table on a plane or the check-in desk at your hotel. Get plenty of rest to keep your immune system working as well as it can.

If you're traveling to one of the CDC's high-risk areas, minimize your exposure to bacteria by using hand sanitizer before and after eating and using the bathroom. Drink bottled water and avoid eating undercooked meat, food made by street vendors and raw fruits and vegetables that have been rinsed in tap water.