The flu we associate with winter spikes when the temperatures and humidity drop, but that's not the case in other parts of the world.
The University of Arizona worked on a study with other universities and found that in places that don't get as cold see a spike in flu cases when the humidity rises and rainfall reaches its peak.
The study is published in the peer-reviewed journal Plos Pathogens, which focuses on microbes.
One of the six named authors is University of Arizona Provost Andrew Comrie, a professor in the School of Geography and Development.
The authors say that understanding how the flu changes depending on climate is important for those working to reduce its prevalence.