I think you have it backwards. The thermometer in your carport is showing artificially high due to the heat released from the house and (likely) concrete of the carport, as well as the carport blocking or reflecting heat that would have been radiating into space. There's also the effect at night that can cool the lower six feet of the atmosphere such that the indicated air temperature of a sensor at the nominal 6' height shows 38 F, but there is frost at the ground level.