This was reported a few years ago, that most (99%) of all temp sensors are located where they are affected by higher temps, such as being located over pavement, near air conditioner heat exchangers, and on top of buildings.
It has been reported, but (1) 99% of the news media — even conservative news outlets and talk shows — have completely ignored this story, and (2) Anthony Watts is just about to come out with a new peer-reviewed scientific journal article on this