I changed my environment to use the identical set of 1,218 stations for GHCN HCN daily data, as are used for the  USHCN monthly data.

We are of course familiar with the hockey stick of data tampering being done between raw and final USHCN monthly data.

 But it is worse than it seems. Before they even to get to “raw monthly” data, they have already cooled the past by 0.1ºF relative to their raw daily data.

There seems to be no limit to the amount of cheating being done with the temperature record.