Can Cold Temperatures Make You Sick? The Real Reason Kids Get Sick More Often During Winter

The simple answer? No. Cold temperatures themselves don’t make you sick (1) — viruses and bacteria do.

The more complex answer? Yes and no. Colds, the flu, RSV, and other seasonal illnesses are caused by viruses, not by chilly air. You can’t “catch” a cold just from being outside without a jacket. However, cold weather does create an environment where viruses can spread more easily, and exposure to cold temperatures may cause your body to be more susceptible to these viruses (1).

Let’s take a look at the contributing factors:

Colder weather tends to equate to more time spent indoors with windows closed, limiting fresh air circulation. Schools, daycare centers, and other indoor gathering spaces can become hotspots for sharing germs because of the close contact, shared surfaces, and less ventilation. This makes it easier for viruses to spread from person to person, especially among kids who are in constant contact with peers and shared objects (2).

To learn about what to do after exposure to a sick person, read this article: What to Do After Exposure to a Sick Person: Immune Support Tips for Families

Many respiratory viruses, like the flu and RSV, survive longer in cooler, drier environments (3). The dry air inside heated homes, schools and workplaces can also dry out the protective mucus in the nose and throat (4), making it easier for viruses to invade, bringing us to our next point.

The mucosal lining in the nose and respiratory tract acts as the body’s first line of defense against germs (5). It’s coated with a thin layer of mucus that traps viruses, bacteria, and other particles, preventing them from entering the body.

In cold, dry air, this protective mucus can dry out and become less effective at trapping pathogens. Additionally, the tiny hair-like structures called cilia, which help move mucus and trapped germs out of the airways, don’t function as well in dry conditions (6), potentially making it easier for viruses to linger and invade. Prolonged dryness could even cause tiny cracks in the mucosal tissue, creating openings for viruses to slip through more easily.

To learn more about using nasal sprays for upper respiratory protection, read this article: How To Buy Or Make Antiseptic Mouth Rinses and Nasal Sprays

Shorter days and less time outside in winter mean kids get less sunlight, leading to lower vitamin D levels (7). Sufficient vitamin D intake is important for immune health (8), and low levels have been linked to a higher risk of respiratory illnesses (9). While some vitamin D comes from foods like fatty fish and egg yolks, sunlight is the main source, making supplementation especially helpful during colder months.

To learn more about vitamin D supplementation, read this article: Better Together: Vitamins D3 & K2

While cold temperatures don’t directly cause illness, they can influence immune function (10). This remains a topic of ongoing research, but we know that cold exposure triggers stress responses in the body, increasing hormones like norepinephrine and cortisol, which can temporarily alter immune activity (10).

Interestingly, brief cold exposure may stimulate immune responses, but prolonged exposure — especially when combined with physical exertion — may suppress immunity (10), potentially making you more prone to getting sick when exposed to germs.

Let’s dispel some common myths about cold exposure and sickness:

• Myth: Going outside with wet hair will make you sick.
  Fact: Wet hair might make you feel cold, but you won't get sick unless you’re exposed to a virus.

• Myth: Not wearing a hat will cause an ear infection.
  Fact: Ear infections are caused by bacteria or viruses, not by cold air. However, keeping your ears covered in extreme cold can prevent discomfort and frostbite.

• Myth: You can “catch” a cold from being outside in the cold.
  Fact: The common cold is caused by a viral infection. You need to come into contact with a virus to get sick, regardless of the weather.

While cold weather doesn’t cause illness in and of itself, extreme cold can still be dangerous, especially for infants and young children. As a general rule, babies should wear one more layer than adults to maintain warmth and comfort. Fingers, toes, and ears are especially vulnerable to the cold, so check them frequently when outside. Watch for signs of frostbite, such as numbness and grayish or pale skin, as well as signs of hypothermia, which can include intense shivering, slurred speech, drowsiness, and confusion.

While you can’t completely prevent your kids from getting sick, especially if they’re in school or daycare, you can support their immune systems to help them fight off infections more effectively.

To learn more about what to expect in terms of sickness frequency in kids by age, read this article: Does My Child Get Sick Too Often? Understanding Sickness Frequency in Children

Focus on providing your kids with a nutrient-dense diet that includes plenty of colorful fruits and vegetables rich in vitamins A, C, and D, as well as zinc to support immune function. For tips on sneaking nutrients into picky kids, read this article: Nutrient & Calorie Dense Foods That Help Underweight Kids Thrive.