Though the worst of flu season seems to have already passed, this season was already much harsher one than the one from last year. Researchers believe that the severity and timing of influenza outbreaks is linked to the weather of the last winter. They theorize that warm winters could cause worse flu outbreaks - and that they could only get worse as climate change wreaks havoc on temperatures.

Researchers from the Centers of Disease Control and Prevention looked at government data for every flu season starting from the year 1997. They noticed that the 2011-2012 winter was one of the warmest on record. Interestingly, the flu season this year was unusually severe and early. They found that winters that were uncharacteristically warmer than average led to more severe flu seasons the following winter. In fact, according to HealthDay, when winters were warmer than average, the flu season the following winter was unusually severe 72 percent of the time.

Researchers believe that the problem lies in vaccination and infection. The influenza virus has a more difficult time surviving when the weather is warm and humid. Therefore, fewer people become infected during warmer winters - and fewer people receive the flu shot. The following winter, that means that fewer people have the immune resistance that they would have if they had gotten sick or the flu shot the winter before - meaning that they are rather defenseless when the flu sneaks up on them.

However, researchers are hesitant about the theory. As Scientific American reports, new versions of the virus can appear through the mixing and blending of influenza in its various hosts. That means that a person who received a flu shot last year may not be protected this year, which is why health officials urge everyone over the age of six years old to receive a flu shot every single year.

However, the findings could mean the development of a flu outbreak forecaster. Currently the CDC has no disease forecaster in place for the flu.

The CDC says that an estimated 36,000 Americans die from the flu every year.

The study was published in the journal PLoS One: Influenza.