The Pima County Health Department warns monsoons can bring mosquitoes and cases of West Nile virus.
Last year, the county reported 33 cases of residents contracting the virus, which is spread by female mosquitoes.
The Arizona Department of Health reported, seven people died from West Nile last year in the state.
Rain creates stagnant pools of water where mosquitoes like to breed, said Priscilla Urbina of the Pima County Health Department. She said these pools can be a hotbed for West Nile activity.
"We always tell people to take precautions, particularly later in the evening when mosquito activity is the highest, by wearing some kind of mosquito repellent...long sleeves (and) long pants," Urbina said. "Oftentimes, mosquitoes will come out from shrubs (or) tall grasses and come out and bite."
So far this year, mosquito populations tested by the department have not shown cases of West Nile, Urbina said.