Q Why do flu viruses seem to circulate more in the fall and winter?
A In Wisconsin and many other parts of the northern hemisphere, the flu virus enjoys a perfect storm of conditions for its seasonal act.
First, the virus has been shown to transmit more easily when the air is drier and temperatures are cooler, says Jonathan Temte of the Department of Family Medicine in the UW School of Medicine and Public Health. “When we plot flu occurrence with temperature, it picks up when the average temperature hits freezing and goes away when average temperatures rise above the freezing point. There is a very strong correlation with temperatures at the freezing mark and flu circulation.”