I guarantee you that they didn't use the same thermometers for every one of these years. They selected the temp readings that would give them the desired statistics.
With winter approaching, ask the Warmist nut jobs this question: "Will a colder than average winter be a sign of global cooling?"...answer: "No, that would be a sign of global warming."...then ask: "Would a warmer than average winter be a sign of global cooling?"...answer: "Don't be silly, that would be a sign of global warming."...then ask: "What would be a sign of global cooling?".
Go ask one them before winter starts, you'll see that I'm right.
I know people like this, A couple are practicing scientists at a university. No conceivable phenomenon could be an indication of anything but Global Warming. Every possible event and its opposite would be Proof Positive for Global Warming.
To be fair, I don't think any scientist would use the phrase 'a sign of'. Whether global warming proponent or sceptic, he would say, in both cases, 'consistent with'. A warm or a cold winter in any one region is weather. Global change is climate. The inability to understand the distinction between weather and climate is the underlying conceptual error which is the greatest souce of confusion in the political, media and popular (as distinct from the scientific debate) on this issue. A certain direction of change in the one does not imply the same direction of change in the other. All climate models, from all sides of the argument, assume the persistence of huge regional, local and temporal anomalies around a norm.