Spot measurements include tricks like using a weather station that was once in the countryside but now is in an airport. They can then show how greatly the climate has changed over the years; you would not know that the spot was in the country at one time.
I know. Urban spawl has destroyed the environment in which the instruments are located.
They’re supposed to be specific distances from obstructions based on the height of the tree or building, but as stuff is built, it encroaches in that space.