It's been a busy month for auto theft detectives at the Dallas Police Department.
NBC 5 has learned 415 cars were stolen in the first two weeks of July -- that's more than one car every hour.
Police are worried the numbers will only get worse as the temperatures get hotter in August. Experienced police detectives said the summer sun can cause responsible drivers to make bad decisions.
"It is the hottest time in Texas. There will be cars that will be taken with keys in it," said Detective Robert Benitez, a DPD Auto Theft Detective
Police say with temperatures so hot in the summer, it's hard to resist the temptation to the leave car on---with the AC blasting---when you're running errands.
"Nobody thinks they'll be a victim. Nobody is a victim until you are. And then the panic hits you," said Detective Benitez.
Benitez said he sees it every day--people run into their local laundry mat, grocery store, or gas station for only a second, and they leave the car running, doors unlocked, because they want to come back to a cool car.
"They might leave the vehicle running. But that decision, that 15 or 20 seconds, can cost you your vehicle. I see this all the time," he said.
NBC 5 dug up the numbers in Dallas that show a summer spike in stolen cars.
In July of 2013, 717 cars were stolen, and more than 650 were stolen in August.
In April 2014, there were about 560 stolen cars. That's a 22 percent drop.
Before arriving for the interview with NBC 5, Benitez was busy filling out a stolen vehicle report for a woman who left her car unlocked, air conditioning running, after returning from the laundromat.
"They were putting their clothes up, they had just run inside, then a suspect took off in the vehicle. They left it running because they were taking their clothes into the apartment. This happens every day in this city."
Benitez shared a clever piece of advice -- he said since taking selfies is so popular these days, it's a great idea to take one selfie with you and your license plate in the background.
"That way you'll always have that information handy," he said. "And that information is critical."
He said every minute police have to wait around for a victim to find out her license plate number makes recovering a vehicle much more difficult.