DENVER – Temperatures are finally dropping in the Denver metro area, which is a good thing for our mountains but a bad thing for people who “puff” their vehicles during the winter months.

That’s why the Denver Police Department is once again warning drivers against “puffing,” or leaving a car running while the driver is away.

In a Facebook video posted this week, the police department – along with a spokeswoman for Rocky Mountain Insurance Information Association – gave followers a few tips and also some dire statistics about auto theft in the state.

Here’s what the police department suggests so you don’t fall victim to thieves during the winter:

1. Lock your vehicle. Police said that up to 50 percent of personal property thefts are due to people leaving their car doors unlocked and the keys in the ignition or in the streets.

2. Remove valuables from your car. Keep things that are of value to you away from the sight of potential thieves and bring those things with you if you’re going to be away from your car for a prolonged amount of time. Don’t leave things in your trunk or in your glove compartment, unless you have the ability to lock it.

3. See something? Say something! Police work hard to keep you safe, but they can’t be everywhere at the same time. That’s why it’s very important to report criminal behavior by calling the Denver Police Department at (720) 913-2000.

Vehicle thefts in Colorado have increased 57 percent since 2014 – that’s an average of 50 cars stolen every day across the state, according to statistics from the police department.

“Puffing” is common on frigid Colorado winter mornings, but can leave the driver with a ticket because the practice makes cars vulnerable to theft. Drivers who have remote-start systems are exempt from the law, except if the vehicle has been idling for longer than 5 minutes. Any vehicle that has been idling for more than 5 minutes, whether on public or private property, is subject to citation, according to Denver police officials.

"The only time everyone is exempt from the puffer law, is if the temperature has been below 20 degrees Fahrenheit for the last 24 hours or if the temperature has been below 10 degrees Fahrenheit for the last hour," according to police.