Outside Air Temperature Guage

[Blutob2]

I only have 1000 miles on the car and I've noticed the outside air temperature is always slow to update. Sometimes it will take 15-20 min of driving before it changes. The car sits in the garage so usually the temp difference is over 20 degrees in the morning as well as once I arrive at work to leaving afterwards. Once it starts to change it rapidly corrects itself but just wondering why it's always so slow to update.