12 Science-Backed Answers to the Question: Does Cold Weather Make You Sick?
3. Dry Indoor Air and Mucus Function
Heating our homes in winter often lowers indoor humidity. Dry air dries out mucous membranes in the nose and throat, which makes it harder for mucus to trap viruses and bacteria. Research and public health guidance note that more hydrated mucus helps clear particles and supports local immune responses. A practical approach is to add humidity back into living spaces where it’s safe to do so. Portable humidifiers can raise indoor humidity to more comfortable ranges, generally recommended by many clinicians to stay below levels that encourage mold. Humidity is only one piece of the puzzle, though; proper ventilation matters too. Combining humidity control with fresh-air exchange reduces stale indoor air while keeping mucus in better working order. If you’re using a humidifier, maintain it carefully to avoid microbial growth. For people with asthma or allergies, consult a healthcare provider before changing humidity levels, since different conditions respond differently to these changes.
4. People Crowding Indoors: The Big Behavior Factor
One of the clearest reasons illness spreads more in winter is behavior. Cold weather pushes social life indoors where people mix closely for longer periods. That increases opportunities for respiratory droplets and aerosols to travel between people. Indoor activities like family gatherings, shared transportation, and crowded public spaces create the kind of sustained contact that viruses exploit. The fix here is mostly behavioral, and it’s practical. Improve ventilation in frequently used rooms by cracking a window briefly when weather permits, or using exhaust fans and portable air cleaners with HEPA filters. Space seating when possible and consider masking in crowded indoor settings during peak illness seasons, especially if you or someone you care for is vulnerable. These steps don’t require dramatic lifestyle shifts; they’re small, realistic habits that lower exposure without asking you to hibernate the whole season.
