Read here. Temperature data sets have been so heavily manipulated across the globe that it's difficult to make sense of what is the truth regarding temperatures. Another example of this incredible data buffoonery (fraud?) was found in a metro area of Australia.
"That’s the huge missing link for me in all of the groups who are working with the temperature data, whether they are Australian, US, English, or whatever. They don’t seem to do any quality control, even the most simple “does this result seem right” kind of tests.....It is astonishing to me that at this point in the study of the climate, we still do not have a single agreed upon set of temperature data to work from.....And folks claim that there is a “consensus” about the science? Man, we don’t have “consensus” about the data itself, much less what it means."