Why Cold and Flu Symptoms Increase During Seasonal Changes and How to Stay Protected

Colds and flu infections tend to rise during particular times of the year — most noticeably in the late fall and winter months — for several interconnected reasons. These seasonal patterns are observed every year and are due to a mix of virus behavior, environmental conditions, and human habits that change as the weather cools.

At Generations Family Practice, our team sees this recurring trend because respiratory viruses, such as rhinoviruses (common cold) and influenza viruses (flu), thrive in conditions that are common in colder months. Several biological and social factors collaborate to make certain seasons more favorable to these infections:

1. Lower humidity and cooler air allow viruses to survive longer outside the body. Influenza viruses, in particular, remain stable and infectious longer when it’s cold and dry.

2. People spend more time indoors when temperatures drop, giving viruses more opportunities to spread from person to person in crowded or poorly ventilated spaces.

3. Seasonal changes can affect the body’s natural defenses, making it slightly easier for viruses to establish infection.

Each of these plays a role in why we see a predictable rise in cold and flu cases in colder months every year.

Cooler weather can directly influence the way cold and flu viruses spread and infect people. Although it may seem counterintuitive — because cold weather itself doesn’t make you sick — the conditions that come with cooler weather create an environment that helps respiratory viruses survive and transmit more efficiently.

Here’s how cooler weather contributes:

1. Viral Stability Increases

When the air is cold and dry, the outer coating of certain viruses, especially influenza, becomes more stable. This stability means the virus can remain infectious for longer periods on surfaces or in aerosol droplets expelled when someone coughs or sneezes.

2. Droplet Transmission Is Enhanced

In dry, cooler air, tiny droplets containing virus particles evaporate more slowly. This allows the droplets to remain airborne longer, increasing the chance that another person will inhale them before they settle on a surface.

3. Nasal Passages Dry Out

Cool, dry air can dry out the mucous membranes in your nose and throat — your body’s first line of defense against invading pathogens. When these tissues are drier and more irritated, it’s easier for viruses to attach and begin an infection.

4. Reduced Sunlight

Shorter days mean less sunlight exposure, which can reduce natural vitamin D production. Vitamin D plays a role in immune response, and lower levels can be linked with increased susceptibility to infections.

Our providers at Generations Family Practice emphasize that the cooler weather doesn’t cause colds or flu directly, but it creates ideal conditions for viruses to survive and spread, and weakens some of our natural protective barriers.

Another key reason cold and flu cases rise seasonally has to do with behavioral changes — specifically, the fact that people tend to spend more time indoors when it’s cold outside.

1. Increased Close Contact

When families, friends, students, and coworkers gather indoors — whether at home, in classrooms, workplaces, restaurants, or social events — it puts individuals in closer proximity. Respiratory viruses spread most easily through direct contact or breathing in air shared with someone who is infected. The closer you are to others, the more likely it is that infectious droplets will reach you.

2. Poor Ventilation

Many indoor environments in colder months have limited fresh air exchange because windows and doors remain closed. Poor ventilation allows virus particles to “hang around” longer in the air, especially in crowded spaces. This makes it easier for someone to pick up an infection even without direct contact.

3. Shared Surfaces

High‑touch surfaces — like doorknobs, light switches, shared desks, phones, keyboards, elevator buttons, and countertops — are common points of contact indoors. Viruses can survive on these surfaces for hours or even days, and touching a contaminated surface and then your face (mouth, nose, eyes) is a common way people pick up infections.

4. Social and Seasonal Gatherings

Holidays and seasonal events in the fall and winter bring people together in closed spaces more often. Even brief exposure to someone who is shedding the virus can be enough to transmit an infection.

Generations Family Practice providers often counsel patients on these dynamics, especially during cold and flu season, because understanding how behavior influences risk can help people take practical steps to stay healthier.

Seasonal changes do not inherently “turn off” the immune system, but certain conditions associated with seasonal change can influence immune response and increase susceptibility to infection.

1. Less Sunlight and Vitamin D

In the fall and winter months, many people get less sunlight. Sunlight exposure supports natural vitamin D production, which plays an important role in immune regulation. Lower vitamin D levels have been linked in some studies to increased risk of respiratory infections.

2. Stress and Sleep Pattern Changes

Seasonal activities, holiday stress, and shorter daylight hours can affect sleep quality and stress levels — both of which are crucial for maintaining a healthy immune system. Chronic stress and insufficient sleep can impair immune function, making you more vulnerable to viruses.

3. Dietary Shifts

Seasonal eating patterns may include more comfort foods and fewer fresh fruits and vegetables that provide antioxidants and micronutrients essential for immune function. This shift can subtly reduce the body’s ability to defend against pathogens.

4. Cold Air and Mucosal Defense

As mentioned earlier, cold, dry air can affect the mucosal linings of the respiratory tract — your first line of defense against inhaled viruses. When these tissues become dry or irritated, they are less effective at trapping and clearing microbes.

5. Behavioral Factors

The immune system doesn’t weaken because of the weather itself, but behaviors tied to seasonal change — staying indoors, increased close contact, disrupted routines — can indirectly lower immune defenses or overwhelm them with increased viral exposure.

Our team at Generations Family Practice helps patients understand that immune health is multifaceted. While you can’t control the seasons, you can strengthen your immune defenses through healthy habits like:

● Consistent sleep schedules
● Balanced nutrition rich in vitamins and minerals
● Regular physical activity
● Effective stress management practices
● Up‑to‑date vaccinations (e.g., flu shots)

These lifestyle factors support your immune system year‑round and help reduce your chance of getting sick when viruses are circulating more widely.

At Generations Family Practice, we take proactive steps to help you stay protected from cold and flu symptoms, especially during seasonal changes. Our team provides expert advice on prevention, including vaccinations, nutrition, and hygiene. By working with us, you can significantly reduce your risk of catching these common illnesses. For more information, please contact us today or book an appointment online now! We are conveniently located at 1021 Darrington Drive, Suite 101, Cary, NC 27513. We serve patients from Cary NC, Morrisville NC, Apex NC, Southwest Raleigh NC, Olde Raleigh NC, and surrounding areas.