In the Herald Sun, columnist Andrew Bolt has an article called "How not to measure warming".
It details research by Anthony Watts (pdf here ) from surfacestations.org that shows the thermally poor locations of a statistically significant number of U.S. weather stations. A quote from his findings follows:
"In fact, we found that 89 percent of the stations – nearly 9 of every 10 – fail to meet the National Weather Service’s own siting requirements that stations must be 30 meters (about 100 feet) or more away from an artificial heating or radiating/reflecting heat source. In other words, 9 of every 10 stations are likely reporting higher or rising temperatures because they are badly sited.
It gets worse. We observed that changes in the technology of temperature stations over time also has caused them to report a false warming trend. We found major gaps in the data record that were filled in with data from nearby sites, a practice that propagates and compounds errors. We found that adjustments to the data by both NOAA and another government agency, NASA, cause recent temperatures to look even higher.
The conclusion is inescapable: The U.S. temperature record is unreliable."
It's interesting to see an example location of just one of the stations (many more in the links above). Note the MMTS is the temperature measurement device:
Meanwhile thhe US National Climate Data Center has claimed that Watts' findings don't make much difference ... (naturally :-) )