NOAA/NCDC just published their State of the Climate Report for May 2013, and in it, are some claims about global temperature that look just plain wrong when compared to other global data sets.

They claim:

• The combined average temperature over global land and ocean surfaces for May 2013 tied with 1998 and 2005 as the third warmest on record, at 0.66°C (1.19°F) above the 20^th century average of 14.8°C (58.6°F).
• The global land surface temperature was 1.11°C (2.00°F) above the 20^th century average of 11.1°C (52.0°F), also the third warmest May on record. For the ocean, the May global sea surface temperature was 0.49°C (0.88°F) above the 20^th century average of 16.3°C (61.3°F), tying with 2003 and 2009 as the fifth warmest May on record.

NOAA says that GHCN has tied for third warmest Global Temperature in 119 years, but that just doesn’t jibe with Dr. Roy Spencer’s UAH data.

UAH says 0.07°C for May. Source: http://www.drroyspencer.com/2013/06/uah-global-temperature-update-for-may-2013-0-07-deg-c/

The RSS temperature anomaly dataset is also much lower than NCDC is reporting:

Source: http://www.remss.com/data/msu/monthly_time_series/RSS_Monthly_MSU_AMSU_Channel_TTT_Anomalies_Ocean_v03_3.txt

UAH/RSS measure the lower troposphere, instead of the 2 meter surface temperature as done in GHCN by NCDC, and there usually a lower value for UAH/RSS than NCDC surface data for that reason, but the discrepancy usually isn’t this large.

NCDC’s claim also doesn’t jibe with the WeatherBell 2 meter global temperature reanalysis from Ryan Maue, which shows a anomaly value of -0.024C for the global average.

*Note: 2 meter reanalysis map above is for the entire month of May, with final run on May 31st, 2013. It is not for a single day as some suggest.

Even NASA GISS is lower according to their May monthly combined global data which comes in at +0.56°C compared to NCDC’s claimed value of 0.66°C

Source: http://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt

I think one of two things has happened:

1. NCDC may have made some sort of processing error.

2. Due to the circumstantial lateness of the May NOAA SOTC report, this is one of those times where maybe many of the CLIMAT reports are lagging, and they don’t have much of a complete data set. If you watch the numbers after the month they claim, they always change later as more data comes in. Watching the data later may tell us.

One thing is clear, since GISS almost always reads higher than other datasets, including NOAA, and in this case NCDC’s claim is higher than any comparable dataset, it doesn’t seem believable. Perhaps a correction will be forthcoming.