Berkeley says the surface temperature record is golden.
Low temperature readings in Olney, Illinois have declined (blue) since 1895. Not to be outdone by mother nature, USHCN has created a rise by subtracting from older temperatures and adding to newer temperatures.
For 19th century temperatures, USHCN subtracts almost three degrees from thermometer readings, and for the 21st century they add more than one degree to the readings. Their generic explanation is found here.
Good thing USHCN and Hansen got rid of this inconvenient cooling problem. “If the present refuses to get warmer, the past must become cooler.”