Now that autumn is here, people are again asking what impact the changing weather will have on the virus’s spread. The experts don’t have answers yet, but the number of new daily confirmed cases is on the rise and winter will bring a new set of challenges that may make things much worse.

In the early months of the pandemic, scientists speculated warm summer air would hinder the spread of coronavirus. But it didn’t, and researchers found COVID-19 does not show a consistent response to the warmer temperatures and increased humidity summer brings.

Besides the onset of “indoor weather” (there is already a shortage of outdoor heat lamps) and an increase in travel around the holidays (Thanksgiving might look different this year), winter brings the seasonal spread of influenza (fewer than half of Americans get a seasonal flu shot) that could overwhelm a health system still recovering from the disarray caused by COVID-19.

In March, while the COVID-19 pandemic spread across nearly every continent, the Southern Hemisphere braced for a winter flu season that never came. Scientists attribute the record-low numbers of flu cases to the travel restrictions, business and school closures, and social distancing measures put in place to curb the spread COVID-19. Public health experts are hopeful the United States and other northern countries will be spared as well.

However, if lockdowns and social distancing measures are not in place, the flu will spread more readily, leading to the alarming prospect of a flu season on top of the coronavirus pandemic.

Hope for a vaccine has had a chilling effect towards actions people could already be taking to slow the spread of coronavirus. President Trump says a vaccine will be ready within a matter of weeks, but health experts say the country should prepare for a winter without access to vaccination and get ready to hunker down and prepare for the road ahead.