“It’s flu season”: a saying we’ve all heard, one that appears during the time(s) of year in which the flu is at its worst. But sometimes it feels like it’s always flu season. Winter, fall, spring, and even early summer — it seems like the flu ebbs and flows throughout the entire year without much reason, and there is hardly a way to predict it.

This is especially concerning since the flu kills thousands of people every year, particularly young and old people who are the most vulnerable. But researchers are trying to pin down exactly when “flu season” starts and finishes, similar to the way weather forecasters predict the weather: taking data from the present and supplementing it with information about past patterns to construct a future estimate. They mix social media, Google searches, and illness reports with mathematical formulas to create a forecast of the flu.

“We’re definitely at the beginning,” Matthew Biggerstaff, a disease tracker in the influenza branch of the Centers for Disease Control and Prevention (CDC), told The Boston Globe. But they hope that eventually, they’ll be able to “make public health decisions” based on these forecasts.

According to Flu.gov, seasonal flu typically occurs in the fall and winter in the U.S., peaking in January or February, but sometimes stretching well into May and starting as early as October. And while the CDC attempts to track the flu on a weekly basis, tracking the number of cases and deaths, the flu still remains quite evasive.

“Influenza is one of the diseases we know better,” Alessandro Vespignani, a professor at Northeastern University who tracks the spread of disease, told The Boston Globe. “Still, paradoxically, it’s one of the diseases that is most difficult to forecast.”

As a result, plenty of self-starters have launched websites that combine information from the CDC with Google searchers and/or electronic medical records: including Flu Near You, Healthmap Flucast, and GoViral. Last year, the CDC held a contest for the best flu forecasters; the winners were Dr. Jeffrey Shaman and his team at Columbia University, who combined Google Flu Trends with CDC information for a flu forecast.

“This provides people a window into the future and what pathogens might be coming down the pike,” Shaman said. “It may help parents decide when to schedule their children’s play dates or it may also help remind people to think about getting vaccinated for influenza.”

While these various flu forecasts may not always be entirely accurate, they can at least provide people with a little more information to assist them in avoiding the illness. In addition to spurring people to get flu shots, they can also help companies allow their employees to work from home on the weeks with highest risk of transmission, and allow people to adjust their precautions and schedules accordingly.