When parked in the sun for a long period of time the ambient temperature will read 10-20 degrees higher then the actual outside temperature. Once the car is moving the ambient temperature normalizes.
Is there an explanation for this.

Thanks JH

 

Partially due to heat soak from the engine and partially due to solar insolation (nice big word, eh?) on the painted surface of the car leading to temps greater than ambient air at the OAT(outside air temp) sensor which is located in the left front wheel well.

 

I find that this is due to parking on asphalt.
Best Regards.......Bob