When is Flu Season?

Published June 24th, 2022 by Chris Riley
Fact Checked by
Jacqueline Hensler
Medically Reviewed:
Erik Rivera

The flu is a highly contagious virus that affects the respiratory system. It is most commonly spread through coughing and sneezing and can cause fever, body aches, and congestion.

Flu season typically runs from October to May, but the dates can vary from season to season depending on the region and other factors.

The Centers for Disease Control and Prevention (CDC) monitors flu cases throughout the country and provides updates on when and where outbreaks are occurring.

In this article we will discuss the flu and its symptoms, when is flu season, as well as different ways to prevent the flu.

What is the flu?

The flu is a contagious respiratory illness caused by influenza viruses and it can cause mild to severe illness and even death.

It can infect the nose, lungs, and throat and often comes on suddenly with the onset of symptoms coming in hours.

The flu is different from the common cold, which tends to come on gradually and has less severe symptoms.

The flu is typically spread when an infected person coughs or sneezes and respiratory droplets containing the virus are expelled into the air and can be inhaled by another person.

Another way the flu is also spread is when a person touches a surface that has been contaminated with the virus and then touches their own mouth, nose, or eyes.

flu sick individual

According to a Centers for Disease Control and Prevention (CDC) study published in Clinical Infectious Diseases, an average of 8% of people in the United States contract the flu every year with children being the most likely to get it although the numbers can vary.

What are the symptoms of the flu?

Flu symptoms typically take one to four days to develop after a person has been infected and symptoms typically last up to five to seven after first showing symptoms although it can be longer.

The most common symptoms of the flu include:

  • Fever
  • Chills
  • Coughing
  • Sore throat
  • Runny nose
  • Headache
  • Body or muscle aches
  • Fatigue
  • Weakness

You may also experience vomiting and diarrhea when you have the flu although it is more common in children than in adults.

If you are experiencing these symptoms, it is important to see your doctor as soon as possible as the flu can lead to serious complications, particularly in young children, pregnant women, seniors, and if you have underlying medical conditions.

What is flu season?

You can get the flu year-round, however, there is a period in the fall and winter when there is peak flu activity compared to the rest of the year and this is called flu season.

The reason it peaks in the colder months is that the weather is conducive to the virus surviving and spreading and the fact our nasal passages are drier due to the dry air which also helps it spread.

Also, you are more likely to be indoors around other people during these months which makes it easier to spread from person to person.

The typical flu season begins in October and peaks between December and February but it can last as late as May in the northern hemisphere although the dates can vary from year to year.

The dates for the flu season are monitored by the CDC which tracks when cases of the flu start to increase and when they start to decrease.

When is Flu Season? 

What are the treatment options for the flu?

The CDC recommends antiviral drugs to treat the flu infection if you have it. Antiviral drugs work by attacking the influenza virus and can make symptoms milder and shorten the duration of the illness. These drugs are most effective with prompt treatment when taken within 48 hours of when your symptoms start but they can still be helpful if taken after that time frame. There are four antiviral treatment options that have been approved by the FDA to treat the flu during the current flu season:

  • Oseltamivir (Tamiflu and it is also available in a generic version too)
  • Zanamivir (Relenza)
  • Peramivir (Rapivab)
  • Baloxavir marboxil (Xofluza)

You can talk to your doctor or health care provider about which of these antiviral drugs is right for you.

Do the dates of the flu season change every year?

The dates for the flu season can change from year to year and are typically monitored by the CDC.

The reason the dates can change is that the weather patterns can be different from year to year which can impact when the flu season begins and ends, variances between regions, and other factors such as more of the population wearing masks during the COVID-19 pandemic.

How does the CDC monitor flu cases?

The CDC monitors influenza activity by tracking when cases of the flu and they track flu activity year-round.

They do this through a surveillance system that includes sentinel providers, state and local health departments, clinical laboratories, and other partners.

The sentinel providers are a group of doctors and nurses who report flu activity in their area to the CDC.

The state and local health departments track the number of people who have gone to the doctor with a flu-like illness or flu hospitalizations and they also track laboratory data on the types of flu viruses that are circulating.

All of this information is then reported to the CDC which uses it to monitor flu activity and make recommendations on when the flu season begins and ends.

They also produce a weekly summary report called the "Weekly U.S. Influenza Summary Update" but the numbers taken are from two weeks prior as it takes roughly a week to compile the report.

Are there ways to prevent the flu?

Yes, there are a few things you can do to help prevent the spread of the flu:

  • Get a flu vaccination each year
  • Wash your hands often with soap and water or an alcohol-based hand sanitizer
  • Avoid touching your eyes, nose, and mouth
  • Stay away from people who are sick
  • Cover your mouth and nose when you sneeze or cough with a tissue or your sleeve (not your hands)
  • Clean and disinfect surfaces that may be contaminated with the flu virus
  • If you are sick, stay home for at least 24 hours after your fever is gone without the use of fever-reducing medicine

All seasonal flu vaccines are quadrivalent vaccines, meaning they protect against four different flu viruses, two influenza A viruses and two influenza B viruses.

The composition of the flu vaccine is reviewed each year and may be updated by vaccine providers based on which dominant strain is circulating and how well they match the flu strains in the vaccine.

Also, take any prescription medications to treat the flu as directed to help treat the flu and lessen any symptoms you may experience.

Taking your medications as prescribed if you are an at-risk individual with underlying chronic health conditions lowers your risk for hospitalization and could be the difference between mild symptoms and severe symptoms that require a hospital stay.


Flu season typically begins in October and ends in May with peak activity occurring between December and February although the dates can change from year to year based on a variety of factors.

Antiviral drugs are the most effective when taken within 48 hours of when your symptoms start but they can still be helpful if taken after that time frame.

There are four different types of flu vaccines that are quadrivalent and protect against four different respiratory viruses that are different strains of the flu.

You should get a flu vaccine every year to help prevent getting the flu and mitigate any symptoms if you get it.

You can help prevent the spread of the flu by getting a flu vaccine, washing your hands often, avoiding touching your face, staying away from people who are sick, covering any cough or sneeze, and cleaning contaminated surfaces.

If you do get the flu, stay home for at least 24 hours after your fever is gone without the use of fever-reducing medicine and take any prescribed medications as directed.

If you have any more questions about the flu or flu season, please talk to your doctor or health care provider.

Research, Studies, and Sources:

Clinical Infectious Diseases 


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