You are more likely to catch colds during winter than in summer. Cold weather itself doesn’t cause colds, but it helps them spread. Many viruses, like the flu and COVID-19, thrive in cold, dry air. These conditions keep viruses infectious longer and help them multiply faster.
Cold weather also weakens the immune system, making it harder to fight infections. Still, viruses and bacteria—not the cold—are the real cause of illness.
Why are Certain Illnesses More Common in Winter?
Respiratory illness spreads through droplets when people sneeze, cough, or talk. Touching contaminated surfaces and then touching your face spreads them, too. In winter, people stay indoors more, increasing close contact with others.
Cold air weakens the nose’s ability to fight infections effectively. Normally, the nose releases vesicles that trap and stop viruses from spreading. When the nose gets cold, this defense weakens, allowing viruses to develop.
A drop in nasal temperature from 98.6 to 89.6 degrees helps viruses spread. Winter’s dry air also reduces humidity, which impacts the nose’s defenses. Heated indoor air dries out the nose, making it easier for viruses to enter. Tiny nose structures called cilia stop working well in dry air. Immune cells also release fewer virus-fighting chemicals in arid conditions.
In humid air, viruses fall faster because droplets stick to water molecules. Even tropical areas can see infections if humidity drops low enough.
Less sunlight during winter lowers vitamin D levels, weakening the immune system. Snowy or icy conditions also reduce exercise, further weakening immunity.
How to Stay Healthy in Winter
Vaccines are the best defense against respiratory illnesses like the flu and COVID-19. Everyone six months and older should get flu and updated COVID-19 vaccines. RSV vaccines are recommended for older adults, pregnant women, and infants.
Wear hats and gloves to stay warm during cold weather. Wearing masks traps warmth around your nose and limits virus exposure.
Avoid touching your face to prevent spreading germs. Cough or sneeze into your arm or a tissue, not your hands.
Stay home if you’re sick to avoid spreading illness to others. Wash your hands often with soap and water to reduce infection risks.
Keep indoor humidity between 40% and 60% to protect against infections. Use a humidifier if your home’s air is too dry.
Eat a healthy diet that includes leafy greens and vitamin D-rich foods. Get regular exercise, manage stress, and aim for enough sleep each night. Avoid smoking and other harmful habits to keep your body strong.
Going outside improves mood, boosts vitamin D, and eases seasonal affective disorder. Fresh air supports well-being, even during cold weather. Most illnesses in winter clear up within a few days at home.
Watch for high fevers, breathing problems, or dehydration, especially in children. Call a doctor if symptoms persist after three or four days. Trust your instincts if symptoms feel severe or unusual.
Conclusion
Understanding how cold weather affects health can help prevent illness this winter. Simple habits like washing hands and getting vaccinated will protect yourself and others.
Have an upcoming trip? Passport Health offers a wide variety of options to help keep you safe from disease, including vaccines. Call or book online to schedule your appointment today.
Logan Hamilton is a health and wellness freelance writer for hire. He’s passionate about crafting crystal-clear, captivating, and credible content that elevates brands and establishes trust. When not writing, Logan can be found hiking, sticking his nose in bizarre books, or playing drums in a local rock band. Find him at loganjameshamilton.com.
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