Outside temp gauge accuracy?

I just came over one of the main bridges that span the harbour in our City and it has a digital temperature reading sign as you ascend.The bridge sign said 13c and my truck read 8c.As I crested,the truck went to 11c,but I conducted a scientific experiment (put my hand out the window),and it felt sub 10,leading me to believe that the truck was closer to correct.

How accurate do you find the trucks reading and where is the sensor?

 

The sensor on the bridge could actually be picking up the heat coming off the structure of the bridge. You're grabbing the actual air temp. This would happen all the time going through a big city. If you have the opportunity, keep an eye on the temp. readout. If it's cold or cool out and you get close to the city and it's been sunny all day, the temp gauge will raise a bit.

Used to travel through Hartford Ct. 5 nights a week enroute to mid-state NY from Boston. I-84 runs through and actually under Hartford. The outside temp gauge on the big truck would climb a few degrees and then drop after you cleared the city and it's buildings/structures/concrete stuff.

 

Cool insight,and I've said it before I'll say it again....Cool screen name.

 

This past summer there where a few days that the weather was reported as being 94 or 95 degrees. My truck read 108 to 110. This was in a rural area. I just figured it wasn't very accurate.

GA