Skip to content

NCDC Introduce More Temperature Adjustments–And Guess Which Way They Go!

March 27, 2014

By Paul Homewood


NCDC have introduced a new method this month of calculating state, (but not national) temperatures in the US.


This is what they say about the old system.




And the new system.




It will come as no surprise to anyone, that the new system makes the past cooler again. For instance, Alabama:






Fortunately, I did an exercise a while ago, comparing NCDC temperatures for Alabama, with the original State Climatological Reports. Therefore we can directly compare the old and new systems.

The temperatures used in that exercise relate to November 1934 & 2011.



  Nov 1934 Nov 2011 Difference
NCDC Before 57.0F 55.5F 1.5F
NCDC After 55.8F 55.3F 0.5F
Difference 1.2F -0.2F -1.0F


So the changeover has resulted in a reduction of 1934 temperatures, relative to 2011, of 1.0F. This is consistent with the above graph.

The old and new versions of Alabama temperatures can also be seen below, (the first being the old version taken from my post at the time). Notice how the trend has increased.






My analysis of USHCN stations in Alabama, in the above mentioned exercise, suggested that the state temperature, under the old system, was already understating 1930’s temperatures, and consequently overstating warming trends. The latest tranche of adjustments have now added to that cooling of the past.


It needs to be restated that the national figures remain, to all intents and purposes, unaffected. This is because they were already calculated under the new system. This now explains why a weighted national average, calculated from NCDC’s own State figures, showed higher temperatures for 1934 than the national figure given by NCDC. When I looked at it last year, I reckoned that this extra set of adjustments added 0.4F to the warming since 1934.


NCDC, at least, provide a tool, which enables you to look at the changes made under the new system,which gives the graph which I showed above for Alabama. You can see just how much they are adjusting past temperatures downwards, by State or Region. It is accessible here . Go play!

  1. Dave E permalink
    March 28, 2014 11:50 am

    No other way to describe this than totally unscientific manipulative cheating to support the unsupportable!
    What was it that was said about statistics being lies in the hands of liars? Maybe I’ve got that last memory a bit adrift, but it certainly seems to be the case that the “pause” is causing a lot of panicky thought amongst the Warmistas.
    Great work Mr H!

    More please.

  2. A C Osborn permalink
    March 28, 2014 11:54 am

    They can’t help themselves, the current Climate is not cooperating, so they have to change the past to maintain the “Warmest Ever” meme.

  3. Andy DC permalink
    March 28, 2014 1:46 pm

    That is what happens when you mix a political agenda with science. Especially when billions of dollars are at stake for the scientists. Also, while at the same time, independent minded “sceptics” are excluded from the process. You could not invent a system that could be any more corrupt.

  4. March 28, 2014 9:53 pm

    Thanks, Paul. Good article; very good find.
    For Florida, shows a cooling of some 0.25 to 0.5°F in the times (from 1885) before 1981.
    I will be pointing this out in my page “Observatorio ARVAL – Meteorology for South Florida and the Caribbean”.

  5. March 29, 2014 2:38 pm

    Reblogged this on CraigM350.

Comments are closed.

%d bloggers like this: