This is the official graph of US temperature since 1890 published by NOAA.
Now here is a graph taken from the USHCN data set. Pretty much the same story. Cooled from 1930 – 1970 but warming up ever since to the point where we are now at the hottest point for the whole time we have been measuring land temperature. But notice the word “FINAL” in the title. This is a graph of adjusted data.
Here is the same dataset but this time, “RAW” data is being used rather than the “FINAL” adjusted data. Much different story. Same runup of temperatures from 1890-1930, but now 1934 appears to be much hotter than the present and there is a clear cooling trend since then. Even the last 10 years are extremely different.
This is an excerpt from – Data Tampering – Land Temperature Record if you would like to explore this further.