Health experts say it's still important for people to protect themselves from West Nile-carrying mosquitoes despite cooler temperatures.
Ned Walker is an entomologist and associate professor in Michigan State University's department of microbiology and molecular genetics.
He says mosquitoes will continue their blood feeding as long as there's, "any kind of warm weather.''
And Walker says that's typically through November.
While some northern reaches of the state already are dipping into the 30s at night, afternoons are generally warm. In the Detroit area, where temperatures have been slightly below normal, the National Weather Service predicts afternoon highs in the 60s and 70s in the coming weeks.
The Michigan Department of Community Health says the number of West Niles cases in the state has grown to 268.
State health officials say 11 people have died from the mosquito-borne virus.