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NOAA’s “Hottest Month” Claims Are Unscientific

June 24, 2014

By Paul Homewood  





It’s not that I’m particularly prescient, but today’s headlines, prompted by the latest NOAA press release, rather substantiates the point I was making last week.


The Telegraph (and no doubt many other outlets) report:


Driven by exceptionally warm ocean waters, Earth smashed a record for heat in May and is likely to keep on breaking high temperature marks, experts have said.

May’s average temperature on Earth of 15.54 degrees Celsius was the warmest since records began in 1880, according to the National Oceanic and Atmospheric Administration



 So let’s recap:


NOAA’s own figures give an error margin for their figures of +/- 0.07C. When this is allowed for, May 2014 statistically joins an eight-way tie as the hottest May, all since 1998. The other years being:

1998, 2001, 2003, 2005, 2010, 2012, and 2013.


Statistically, their claim of the “hottest month” does not hold water.


We should also bear in mind just how sparse their temperature data coverage really is.





Finally, we can take a look at what the satellites have to say.







RSS show May 2014 as only the 6th warmest, while on UAH it ranks 3rd. Both datasets show May 1998 as by far the warmest month.


NOAA’s reporting on this is unscientific, irresponsible and seems to be designed to create a deliberately political and alarmist message.

  1. Jbird permalink
    June 24, 2014 1:32 pm

    Interesting they should report something like this while selectively ignoring their own data that shows overall declining temps in the past 9-10 years. Do you suppose they have some kind of agenda?

  2. June 24, 2014 2:19 pm

    Even taking the NOAA data at face value the Telegraph headline is misleading.
    “May was the hottest ever for Earth”
    What the meant was it was the hottest May on record.
    Overall it was only the joint 13th hottest of any month.
    I suspect they are being deliberately “economical with the truth”,

  3. June 24, 2014 2:21 pm

    Sorry I mistyped the headline.
    It should have been:
    “May was the hottest month ever for Earth”

  4. BallBounces permalink
    June 24, 2014 2:28 pm

    “NOAA’s reporting… seems to be designed to create a deliberately political and alarmist message.”

    Headlines are remembered long after alternate opinions and corrections are forgotten.

  5. ralphcramdo permalink
    June 24, 2014 2:42 pm

    The EPA says they’re wrong according to their heat wave index.

  6. June 24, 2014 4:01 pm

    I noticed that Josie Ensor added the anomaly for May to the 1901-2000 average to get the absolute the absolute temp. when claiming it was the “hottest month ever”.

    “May’s average temperature on Earth of 15.54 degrees Celsius was the warmest since records began in 1880, according to the National Oceanic and Atmospheric Administration.”

    I wondered if this would make the claim true in that other months might have a lower absolute temperature, while have a higher anomaly.

    So I added the anomalies from previous years to the averages to get the absolute temperature for each month. It turns out that it’s even worse (for the warmists) using this method.

    May 2014 at 15.54c is only the joint 256th. warmest month (out of 1613),. Of course the NH summer months predominate in the highest values, because for some reason the Earth is warmer in NH summer.

    The month which was the hottest in absolute terms in the NOAA record was July 1998 at 16.53c, assuming the NOAA 1901-2000 averages are correct.

    • David permalink
      June 25, 2014 5:20 am


      The earth is warmer in the NH summer because there is a greater proportion of land mass in the NH than the SH. The oceans absorb more solar energy in the SH summer than they do in the NH summer.

      Re your work: it’s a good point. You often see people saying things like ‘temperatures were up or down on last month’ because the anomaly values for one month were higher or lower than the previous one. They overlook that the monthly anomaly value is compared only against previous temperatures ‘for that month’. You can’t compare a May temperature with an April temperature in terms of anomalies only.

      By the way, this is worth remembering when off-setting a monthly value for comparison with that of a data set that uses a different base period for the anomaly. For instance, to compare May 2014 in NOAA to May 2014 in UAH you need to subtract the average of all ‘May’ values between 1981 and 2010 from the NOAA figure. Using the annual value only works for annual comparisons.

      This may seem a little obvious to you, and I mention it only because it was a mistake I was making myself for a while.

  7. June 24, 2014 4:59 pm

    We shouldn’t be arguing about the semantics of their statistical explanation. Yes, it was the most political way to talk about the fact that it’s hotter now than it was in 1975. But the fact is, it IS hotter now than it was in 1975. The questions should be how it got here and why.

    What we should be focusing on is that there was a nearly stable temperature anomaly from 1975 until 1995, an apparent ramp up from 1995 until about 2002, and from then the temperature anomaly has been relatively stable at the higher mean.

    What we all should be talking about is why was there the step change up and why was it a step change and not a spike that recovered back to the pre-1995 levels?

    No one seems to be talking about cause and effect from a data point of view. They all like to look at the endpoints report that CO2 was lower and now its higher and that the Temperature was lower and now it’s higher, QED, CO2 is the problem. That’s good science in elementary school, but nowhere else. The people at NOAA and at the IPCC are mostly bright and honest Scientists. Don’t they LOOK at the data?

    • Alan Davidson permalink
      June 24, 2014 8:16 pm

      The apparent ramp up from 1995 is entirely due to fraudulent upwards manipulation of worldwide temperature records. Analyses published on a number of websites indicate that real global temperatures have actually been dropping since then i.e. there’s been global cooling not global warming!

      • Dave Matz permalink
        June 25, 2014 1:31 am


        “…entirely due to fraudulent a upward manipulation” is a pretty strong statement. You infer that there are scientific papers that report that. Can you give some references?

        There was a cool dip in 1993 caused by Mt Pinatuba. As it was recovering, there was a strong El Niño peaking temperature in 1998. That seemed to be recovering when there was a 4 year ramp upward until about 2002. Since then the mean temperature seems stable about .3 degrees above the 1975-1992 mean. Why the step change?

        Alan seems to think it is a fraudulent conspiracy. Anyone out there want to confirm that or give a scientific explanation?

      • David permalink
        June 25, 2014 3:24 pm


        Further to Dave’s comment: if we’re going to accuse data producers of fraudulently changing a cooling trend to a warming trend since 1995 then we’ll have to accuse *all* of them. That’s because the all show warming; including both satellite sets.

        In fact, since 1995 Roy Spencer and John Christy’s UAH satellite data set shows the fastest rate of warming of all the producers. It doesn’t strike me as likely that Spencer and Christy, both strong ‘sceptics’ when it comes to some aspects of man-made global warming, are fraudulently manipulating lower troposphere temperatures upwards.

      • June 25, 2014 4:09 pm

        then why did Dr. John Christy state this. Global temperatures collected in five official databases confirm that there has been no statistically significant global warming for the past 17 years, according to Dr. John Christy, professor of atmospheric science and director of the Earth System Science Center at the University of Alabama Huntsville (UAH)

      • David permalink
        June 26, 2014 6:22 am

        Peter Piasecki

        Dr Christy is right to say that no data set shows statistically significant warming over the past 17 years. However, my comment referred to trends since 1995. Since 1995 the ‘best estimate’ trends, i.e. the trends derived from the officially published data from the 5 main producers, are:

        UAH: 0.12 (+/-0.17)
        RSS: 0.03 (+/- 0.17)
        GISS: 0.11 (+/-0.10)
        NOAA: 0.09 (+/-0.10)
        HadCRUT4: 0.09 (+/-0.10)

        [All in deg C/dec with 2-sigma error margins shown.]

        The warmest ‘best estimate’ trend since 1995 is that of UAH. GISS is the only trend that is ‘statistically significant’ since 1995, even though it’s not as fast as UAH. (That’s because the GISS data are less ‘noisy’ than the UAH data over the same period.)

      • June 26, 2014 9:24 am

        The general argument is that 17 years is the furthest you can go back to with no warming.

        There are obviously years in between that can show both warming and cooling trends.

      • David permalink
        June 26, 2014 1:27 pm


        It depends whether you mean ‘best estimate’ warming, i.e., as derived from the official published data from each producer, or ‘statistically significant’ warming, i.e., where the extent of the warming clearly exceeds the limits of the 95% confidence range.

        For ‘best estimate’ warming, I find that a trend started in any month prior to Aug 2008 produces a warming trend in UAH; whereas you have to go back to July 1996 to find the same in RSS. The others are around 2000/01.

        For statistically significant warming I found I had to go back to Oct 1995 for the most recent (GISS); but you can go back as far as May 1989 for the latest (RSS again).

    • Spencer permalink
      June 25, 2014 3:50 pm

      It’s pretty obvious when you notice that the warm up began when PDO the flipped to positive in 1978. The current “hiatus” is due to PDO flipping to negative. When AMO flips to negative also you will see a decline until PDO flips to positive around 2030-35.

      We keep looking for some mystery piece when the answer is right before our eyes. The oceans drive the climate on longer scales…everything else is a very small player & usually only temporary.

  8. Anymoose permalink
    June 24, 2014 6:43 pm

    Some hot month! We got 111″ of snow in Cheyenne during May.

    • Anymoose permalink
      June 24, 2014 6:45 pm

      Make that 11″ of snow.

  9. June 24, 2014 8:54 pm

    Yes but that 11 inches of the warmest snow ever

  10. June 25, 2014 12:49 am

    Reblogged this on the WeatherAction Blog.

  11. Mikky permalink
    June 25, 2014 12:55 pm

    If the latest May figure is a “good” statistic then so must be the slope derived from the previous high May figures:

    Giving a slope of … ZERO!

  12. June 25, 2014 7:38 pm

    On the map above I see that the area where I am is pink, indicating a positive anomaly. That certainly hasn’t been my experience. (Aside from one or two warm days it’s been cool all year.) Of course, it helps to go outside once in a while when considering these issues – could that be the problem?

  13. June 25, 2014 7:49 pm

    I also see that the Telegraph article claims that temperatures were “driven by exceptionally warm ocean waters”. In that case, given the prevailing winds at my location, it should have been “exceptionally warm” instead of cool.

  14. Andy DC permalink
    June 26, 2014 8:33 pm

    It is interesting that there is almost no station data over the huge expanse of Southern Hemisphere oceans. Yet they somehow manage to get a huge percentage of that huge area above normal. Over and over again.

  15. Mcass777 permalink
    August 25, 2014 1:40 am

    In june this was the headline, now there are reports global cooling is related to the sinking of warm water in the Atlantic. What gives?

    • August 25, 2014 9:56 am

      The two things are not incompatible.
      Temperatures could be lower than predicted but still the highest on record.
      The problem is, there is increasing evidence to suggest NOAA figures are untrustworthy, due to tampering. We don’t know any more.


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