Is it necessary to warm up your car in cold weather? It was in the old days, but not so much anymore due to our modern cars. The AAA says you only need to let the engine run for about 30 seconds, or as long as it takes you to get situated and buckled up, before driving. That will give enough time for the oil to circulate. AutoZone notes that some states and cities have laws restricting the practice for environmental reasons and carry fines in excess of $1,000 (Yikes!) Electric cars should be kept plugged-in on cold days, when possible, as they have conditioning systems that can keep their batteries at the ideal operating temperature and can also be programmed to heat the cabin without emitting any tailpipe emissions. The experts say the only time you should really consider an extended warm-up is if you’re having trouble scraping snow and ice off the windows before they’re defrosted, but a good scraper and a can of remover can accelerate the process.