NOAA’s measured temperature data shows April has been cooling in the US since 1930.
NCDC doesn’t publish raw data, and instead published tampered data which shows a strong warming trend.
Note that there are no warnings or disclaimers on that web page indicating that they have reversed the trend by altering the data.
The graph below shows the difference the raw and tampered data. They have progressively adjusted older temperatures downwards, which creates a non-existent warming trend.
Until about ten years ago, NASA, NOAA and CRU all acknowledged that there has been no warming in the US. But that was before they started tampering with the data.
Empirical evidence does not lend much support to the notion that climate is headed precipitately toward more extreme heat and drought. The drought of 1999 covered a smaller area than the 1988 drought, when the Mississippi almost dried up. And 1988 was a temporary inconvenience as compared with repeated droughts during the 1930s “Dust Bowl” that caused an exodus from the prairies, as chronicled in Steinbeck’s Grapes of Wrath.
in the U.S. there has been little temperature change in the past 50 years, the time of rapidly increasing greenhouse gases — in fact, there was a slight cooling throughout much of the country
– James Hansen
February 04, 1989
Last week, scientists from the United States Commerce Department’s National Oceanic and Atmospheric Administration said that a study of temperature readings for the contiguous 48 states over the last century showed there had been no significant change in average temperature over that period. Dr. (Phil) Jones said in a telephone interview today that his own results for the 48 states agreed with those findings.
The animation below shows how NOAA is now cooling the past – to create the impression of a non-existent warming trend.