Cold and Flu Season

In the United States, cold and flu season begins around late August and lasts until March or April. One possible cause of cold and flu season is the opening of schools in the fall, which brings more people in closer proximity to one another. Another possible cause of cold and flu season has to do with changes in relative humidity.

 

Cold and Flu Season: An Introduction

In the United States, most colds and flus occur during the fall and winter (the cold and flu season). Beginning in late August or early September, the rate of colds and flus increases slowly for a few weeks and remains high until March or April, when it declines.
 

Possible Causes of Cold and Flu Season

One possible cause of cold and flu season may relate to the opening of schools and to the arrival of colder weather, which prompt people to spend more time indoors and increase the chances that viruses will spread to you from someone else.
 
Seasonal changes in relative humidity also may affect the prevalence of colds and flus. The most common cold and flu viruses survive better when humidity is low -- during the colder months of the year. Cold weather also may make the inside lining of your nose drier and more vulnerable to viral infection.
 
Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD