Like all temperature data sets, the past has been cooled at UAH, which creates the appearance of warming.
As of 1995, UAH closely matched NOAA radiosonde temperatures and showed no warming after 1979. The graph below is from the 1995 IPCC report
The thick line is UAH, and the thinner line is radiosonde. They were almost a perfect match, with zero warming.
The next graph is the current version of UAH vs. NOAA radiosonde. UAH now shows about 0.4C warming since 1979, about three times as much warming as the radiosonde data.
The next graph shows how the 1979-1995 UAH data has changed since 1995, turning a cooling trend into a warming trend.
UAH has also cooled the past in the US since their 2001 version, having cooled the very warm year of 1995 by almost 0.3C. That year was the year without a winter in the US.
UAH US temperatures diverge sharply from measured US temperatures, warming about 0.3C more since 1979 than the raw surface data.
I don’t see any reason to believe any of the temperature data sets, except for the ones I can process myself from raw data. The US has seen no warming since 1920.