A few years ago, a concerned citizen in the USA began a project to “audit” the official temperatures.
Did not come out well for the official temperature takers.
Very embarrassing.
Here is one of the semi-final reports:
surfacestations.org
More than 70% of the instrument locationss read more than 2Cº above the actual temperatures. What good is that if your computer models show ONE degree over one hundred years??? Your instrument is TWO degrees above before you even start. So your basic data is WAAYYY off.
A lot of the data collection took place at airports and was sufficiently accurate for the purposes of calculating the take off distances needed for airplanes. But it was not sufficiently accurate for scientific purposes.
In fact, the Federal Aviation Administration even has Advisory Circulars describing how the data is to be collected and there is an Advisory Circular with historical data. I will check … maybe some bureaucrat changed the name as his/her contribution to the human record of data.
faa.gov/documentLibrary/media/Advisory_Circular/150_5300_13_chg17_cons_p2.pdf
So, science would demand that the data collection instruments be updated and be relocated away from heat sources such as air conditioning vents.