Bank thermometers will often show erroneous temperatures. It is not so much that the sensor being used is inaccurate, but instead, the sensor is often placed in a poor position. To accurately measure the air temperature, official thermometers have historically been placed in a white shelter box referred to as a Stevenson screen and more recently in a white enclosed ventilated plastic cover.
Often a thermometer used by a business is directly in the Sun part of the day, plus the thermometers are often placed over parking lots that are black and absorb much of the incoming solar radiation and make the surrounding air much warmer. That dark surface influence has been particularly noticeable in recent days as the strong early Spring sunshine has a lot of potential to warm, but our snow pack has been limiting the area from reaching our temperature potential.
So if you see a bank thermometer flashing 50 degrees on a sunny day, the reality is, it would likely really be 50 degrees if it was not for our deep snow cover.