Question about Thermometers - Something That's Puzzling Me . . .

[Ghost_Tracker]

There's something I've been wondering about; I was just hoping somebody in here might have some ideas about it. We have an electronic thermometer in the living room that gives the time and temperature. (It communicates with a sensor outside, of course.)
Now, during the summer in the afternoon, this thing is usually off. Fine, I can understand that easy - the heat from the sun runs up the wood of the house and makes the thing read a bit high. But now it's the middle of winter, and I just noticed - at 10 p.m. or so, well after the sun had set, that it said that it's "28 degrees" outside. Well, there's an airport right near my house - only a half-mile away - and that's where the weather service measures the temperature, for this area - - and they're reporting 24 degrees. Here's the thing - I mentioned it to my Dad and he said that the car thermometer was also reporting 28 degrees. We've noticed similar discrepancies before. There's no significant changes in altitude between my house and the airport. So why would the airport temperature consistently be about 4 or 5 degrees lower than here at the house, only a half-mile away??? . . . .