Adjusting for the UHI effect would have only a small effect on the situation, whereas NOAA has made some pretty drastic changes to the raw data, kinda in the vein of "it's more effective to just lie on your tax form than to bother taking all the legal deductions."
https://principia-scientific.org/how...rd-warm-years/
The land based temp record does show much more variation due to instrumental error, observational error and poorly spaced (and placed) recording sites (like only 2 or 3 sties in the vast polar regions compared to the satellite record. ...Two problems with the satellite records is (a) they only go back to 1979, and [2] they are an exercise in "curve fitting" ---weighting the raw data on irradiance and correlating it to temperature history. That's why they occasionally have to "adjust" their weighting because it's no longer giving an accurate reproduction of the history (everyday the history gets one day longer).
Another problem with paying attention to "average temps" is that we don't really care what the average temp is in practical matters. When we get up each day and get dressed, we want to know OUR temperature, not the average for the planet.....Energy naturally flows from hot to cold, so the tropics have not warmed at all, the temperate zones have only warmed slightly (all at nite, not in the day), and of the ~0.5degC "average" warming we've seen the last 30 yrs, ~2.7degC of it has occurred in the polar regions where nobody lives, bringing the total up in a meaningless way down here where we do live.