WEST Midlands Police is urging drivers not to leave cars defrosting with the engine running after up to £100,000 worth of motors were stolen.
The force is warning car owners it only takes a few seconds for their vehicle to be taken from a driveway or outside their homes on November 29.
People are now being put on their guard against leaving keys in the ignition this winter after thieves struck on separate occasions between 7.30-9.15am.
An Audi A3 was taken from Newton Road, Knowle; a Ford Mondeo from Westfield Close, Dorridge; and a Mazda from Hodnell Close, Castle Bromwich.
Officers are also investigating how thieves managed to obtain the keys and steal a car from Summerfields Avenue, Halesowen.
Opportunist car thieves watch the weather forecast and police are advising car owners not to nip back inside their home when a car is defrosting.
Motorists should stay with their vehicle and use a de-icer spray or scraper to speed up the process.