Mosquitoes are still biting and temperatures are still flirting with 100 degrees, but public health experts already have turned their attention to the flu.
For the first time, the U.S. Centers for Disease Control and Prevention is recommending the flu vaccine for children of all ages, except infants younger than 6 months.
"That's because they're walking germ factories and they seem to be a major contributor to the spread of influenza in the community," said Dr. Karen Lewis, medical director for the state Department of Health Services.
"After 20 years of taking care of kids in hospitals," she said, "I'm just tickled to see there are universal recommendations."
Though Lewis has long seen the need on the front lines, federal officials had to be sure that science, and vaccine manufacturers, could back them up.
This year, a record 143 million doses of flu vaccine are expected to be delivered in the U.S., and many retail flu shot clinics are ramping up this weekend.
The Mollen Clinics will offer thousands of locations statewide, stationed in Albertsons, Fry's, Bashas', Food City and A.J's supermarkets, as well as CVS/pharmacy and WalMart stores.
Health officials are urging people to get vaccinated early, before influenza hits and while there's ample opportunity.
Flu shot clinics and health care providers typically stop offering the vaccine by Thanksgiving, and the holiday hustle pushes "get a flu shot" off the to-do list.
The CDC is trying to change that this year with a campaign to keep the vaccine flowing through January. The agency has moved National Influenza Vaccination Week to mid-December to encourage flu-shot providers to extend their season and remind the public that it's not too late to get immunized.
In Arizona, flu season typically hits its stride later than other parts of the country - in January or February.
Last season was particularly harsh. Flu was widespread in Arizona, the highest CDC designation, for eight consecutive weeks, through February and into March. Two children died, including one who contracted a staph infection linked to influenza.
Lewis said flu sufferers can develop secondary bacterial infections, like staph, because influenza can damage airways.
Though the elderly are most likely to die from influenza, children are hospitalized at the same rate as their grandparents, she said.
Last year's vaccine didn't protect against some of the most virulent strains. But Lewis said vaccine development, on average, proves 90 to 95 percent effective.
Florence Del Prete planned to get a flu shot over the weekend. It's become a routine for two decades.
"I'm 83, so I figured I ought to have something to help," she said. "They say the older you get, you're more likely to get it. And if you do, it's harder on you."
Del Prete knows demand for the shots will increase in the coming weeks, and she doesn't want to be caught in a long line.
"All the snowbirds are coming," she said. "That's why I'm trying to get it early."
Up to 20 percent of people get influenza each year. In Arizona, more than 4,000 are hospitalized and 700 people die.
Those most at risk for complications include young children, those over 50 years old and people with chronic diseases such as asthma, diabetes and heart disease.
Also, health care providers and anyone who lives with or works with those at risk should be vaccinated.