Most of us have a favorite season. Some of us love the budding beauty of spring, while others prefer the falling snow in the winter. But there is one season that doesn’t seem to be anyone’s favorite, and that’s flu season.

Technically, the flu can spread at any time of year. Although infrequent, cases have been reported in even the hottest parts of the summer. But the overwhelming majority of flu infections, and virtually all outbreaks, occur in the fall, winter, and early spring.

The actual dates of the flu season vary among different parts of the world, but always fall during the colder months. Warmer climates have less incidence of the flu, and cooler ones may have a flu season that lasts longer. In the United States, flu season is generally accepted to begin in October and end in May, peaking between December and March.

Traditionally, the bulk of flu cases occur over a period of about six weeks. The peak of the season usually occurs about three weeks after the first cases are reported, and it takes another three weeks for infection rates to diminish. On average, flu season reaches its peak around February in the United States.

Why Is the Flu More Common in Cold Weather?

One thing that is mysterious about the flu to many people is why it is so prevalent in cold weather and nearly nonexistent in warm weather. Part of the reason is because people tend to stay indoors more when it’s cold out, facilitating the rapid spread of germs. It is also believed that the heat and radiation from the sun makes it difficult for viruses in general to survive during warmer months. But according to recent studies, there’s actually a lot more to it than that.

Researchers at the National Institutes of Health have found that the influenza virus coats itself in a fatty, butter-like material. This material hardens in cold temperatures, protecting the virus from the elements. In warm temperatures, the coating melts, leaving the virus vulnerable. It also melts once the virus makes its way into a person or animal’s respiratory tract, but it can survive and replicate there without the added protection.

Getting Ready for the Flu Season

If you plan to get a flu shot, it is best to do so as early as possible. This is especially true if you are at high risk of developing complications from the flu. Children six months to four years of age, the elderly, people with chronic conditions, pregnant women, and those who reside or work in health care facilities or other places where they are likely to come in contact with the virus are some of the people who fall into this category.

If you do not have access to the flu vaccine, or if you prefer not to get it, being vigilant against germs is your best defense. Frequent and thorough hand washing is one of the most important things you can do. A nutritious and balanced diet is also important to keep your immune system in good shape, and supplementation may also be in order. Finally, getting plenty of sleep will help your body fight off the flu virus more easily.