Put your warm clothes on, put your thick doona on the bed and turn the heater up! Over night temperatures will drop to a chilly 6 degrees. Tomorrow is expected to only reach a maximum of 15 degrees. If you think that is bad, spare a thought for poor old Perth! The overnight minimum in Perth with be 2 degrees. It's not all bad news though - especially for Mandurah. Tomorrow will be mostly sunny, with frost in the early morning and light winds expected.