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Note: GHCN-M Data Notice

An omission in processing a correction algorithm led to some small errors on the Global Historical Climatology Network-Monthly dataset (GHCN-M v3.2.0). This led to small errors in the reported land surface temperatures in the October, November, December and Annual U.S. and global climate reports. On February 14, 2013, NCDC fixed this error in its software, included an additional improvement (described below), and implemented both changes as GHCN-M version 3.2.1. With this update to GHCN-M, the Merged Land and Ocean Surface Temperature dataset also is subsequently revised as MLOST version 3.5.3.

The net result of this new version of GHCN-M reveals very small changes in temperature and ranks. The 2012 U.S. temperature is 0.01°F higher than reported in early January, but still remains approximately 1.0°F warmer than the next warmest year, and approximately 3.25°F warmer than the 20th century average. The U.S. annual time series from version 3.2.1 is almost identical to the series from version 3.2.0 and that the 1895-2012 annual temperature trend remains 0.13°F/decade. The trend for certain calendar months changed more than others (discussed below). For the globe, ranks of individual years changed in some instances by a few positions, but global land temperature trends changed no more than 0.01°C/century for any month since 1880.

NCDC uses two correction processes to remove inhomogeneities associated with factors unrelated to climate such as changes in observer practices, instrumentation, and changes in station location and environment that have occurred through time. The first correction for time of observation changes in the United States was inadvertently disabled during late 2012. That algorithm provides for a physically based correction for observing time changes based on station history information. NCDC also routinely runs a .pairwise correction. algorithm that addresses such issues, but in an indirect manner. It successfully corrected for many of the time of observation issues, which minimized the effect of this processing omission.

The version 3.2.1 release also includes the use of updated data to improve quality control and correction processes of other U.S. stations and neighboring stations in Canada and Mexico.

Compared to analyses released in January 2013, the trend for certain calendar months has changed more than others. This effect is related to the seasonal nature of the reintroduced time-of-observation correction. Trends in U.S. winter temperature are higher while trends in summer temperatures are lower. For the globe, ranks of individual years changed in some instances by a few positions, but global temperature trends changed no more than 0.01°C/century for any month since 1880.

More complete information about this issue is available at this supplemental page.

NCDC will not update the static reports from October through December 2012 and the 2012 U.S and Global annual reports, but will use the current dataset (GHCN-M v. 3.2.1 and MLOST v. 3.5.3) for the January 2013 report and other comparisons to previous months and years.

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Global Highlights

  • The average combined global land and ocean surface temperature for October 2012 tied with 2008 as the fifth warmest October on record, at 0.63°C (1.13°F) above the 20th century average of 14.0°C (57.1°F). Records began in 1880.
  • The globally-averaged land surface temperature for October 2012 was the eighth warmest October on record, at 0.92°C (1.66°F) above average. The globally-averaged ocean surface temperature tied with 2004 as the fourth warmest October on record, at 0.52°C (0.94°F) above average.
  • The average combined global land and ocean surface temperature for January–October 2012 was the eighth warmest such period on record, at 0.58°C (1.04°F) above the 20th century average.


Temperature anomalies and percentiles are shown on the gridded maps below. The anomaly map on the left is a product of a merged land surface temperature (Global Historical Climatology Network, GHCN) and sea surface temperature (ERSST.v3b) anomaly analysis developed by Smith et al. (2008). Temperature anomalies for land and ocean are analyzed separately and then merged to form the global analysis. For more information, please visit NCDC's Global Surface Temperature Anomalies page. The October 2012 Global State of the Climate report introduces percentile maps that complement the information provided by the anomaly maps. These new maps on the right provide additional information by placing the temperature anomaly observed for a specific place and time period into historical perspective, showing how the most current month, season or year compares with the past.


In the atmosphere, 500-millibar height pressure anomalies correlate well with temperatures at the Earth's surface. The average position of the upper-level ridges of high pressure and troughs of low pressure—depicted by positive and negative 500-millibar height anomalies on the October 2012 height and anomaly mapOctober 2012 map—is generally reflected by areas of positive and negative temperature anomalies at the surface, respectively.


The average temperature across land and ocean surfaces during October was 14.63°C (58.23°F). This is 0.63°C (1.13°F) above the 20th century average and ties with 2008 as the fifth warmest October on record. The record warmest October occurred in 2003 and the record coldest October occurred in 1912. This is the 332nd consecutive month with an above-average temperature. The last below-average month was February 1985. The last October with a below-average temperature was 1976. The Northern Hemisphere ranked as the seventh warmest October on record, while the Southern Hemisphere ranked as second warmest, behind 1997.

The average global temperature over land was 0.92°C (1.66°F) above average, making this the eighth warmest October on record. Several regions around the globe were much warmer than average, including northeastern and southwestern North America, most of South America, northern Africa, southeastern Europe, southwestern Asia, and far eastern Russia. A heat wave brought record warmth to large areas of Brazil and Bolivia. Record heat was also present in southern India. It was cooler than average in parts of northern Siberia, Mongolia, and northern China along with much of central North America. Western Canada was much cooler than average.

Select national information is highlighted below:
  • The average monthly temperature across the United Kingdom was 1.3°C (2.3°F) below the 1981–2010 average, making this the coldest October since 2003. Regionally, Scotland had its seventh coolest October since records began in 1910 and coolest since 1993.

  • Central and southeastern Europe were warmer than average during October. Temperatures were about 1.1 to 1.6°C (2.0 to 2.9°F) above the 1961–1990 average across large parts of Croatia, particularly in the south and west, while the Republic of Moldova reported monthly temperatures across the country that ranged from 2.5 to 3.5°C (4.5 to 6.3°F) above average.

  • Every state and territory in Australia observed above-average monthly maximum temperatures during October. The nationally-averaged temperature was 1.53°C (2.75°F) above the 1961–1990 average, making this the 10th warmest October maximum temperature since records began in 1950.

The October global sea surface temperature was 0.52°C (0.94°F) above the 20th century average of 15.9°C (60.6°F). This ties with 2004 as the fourth highest on record for October. The northwestern Atlantic Ocean and part of the north central Pacific Ocean temperatures were markedly higher than average. Conversely, much of the eastern and part of the western Pacific Ocean and much of the southern Atlantic Ocean were below average.

Borderline neutral / weak El Niño conditions were present during October across the central and eastern equatorial Pacific Ocean, with sea surface temperatures close to 0.5°C (0.9°F) above average for a three-month period (August-September-October), the official threshold for the onset of El Niño conditions. According to NOAA's Climate Prediction Center, neutral conditions are expected to continue through the Northern Hemisphere winter 2012/13.

October Ranks and Records
(out of 133 years)
Land+0.92 ± 0.12+1.66 ± 0.22Warmest8th2005+1.16+2.09
Ocean+0.52 ± 0.04+0.94 ± 0.07Warmest4th2003+0.59+1.06
Ties: 2004
Land and Ocean+0.63 ± 0.07+1.13 ± 0.13Warmest5th2003+0.73+1.31
Ties: 2008
Northern Hemisphere
Land+0.88 ± 0.11+1.58 ± 0.20Warmest8th2011+1.33+2.39
Ocean+0.55 ± 0.04+0.99 ± 0.07Warmest5th2003, 2006+0.66+1.19
Ties: 1997
Land and Ocean+0.68 ± 0.09+1.22 ± 0.16Warmest7th2003+0.89+1.60
Southern Hemisphere
Land+1.04 ± 0.15+1.87 ± 0.27Warmest4th2006+1.14+2.05
Ocean+0.51 ± 0.04+0.92 ± 0.07Warmest3rd1997+0.59+1.06
Land and Ocean+0.60 ± 0.06+1.08 ± 0.11Warmest2nd1997+0.62+1.12
Ties: 2002
Land and Ocean+0.85 ± 0.27+1.53 ± 0.49Warmest19th1947+1.76+3.17
Ties: 1948
Year-to-date (January–October)

Record to near-record warmth over land from April to September and above-average sea surface temperatures across much of the world's oceans resulted in the first ten months of 2012 ranking as the eighth warmest such period on record, with a combined global land and ocean average surface temperature of 0.58°C (1.04°F) above average. With borderline ENSO-neutral / El Niño conditions continuing to hold during October, this is just slightly higher than the January–September year-to-date temperature of 0.57°C (1.03°F) above average. If this anomalous warmth continues through the end of the year, 2012 will surpass 2011 as the warmest La Niña year since the Climate Predition Center began monitoring ENSO conditions in 1950.

Similar to the January–September period, the global land surface temperature for January–October ranked as eighth warmest and the global sea surface temperature ranked as 10th warmest. Much of the United States, south central Canada, northern Argentina, part of southern Europe, parts of the northwestern and southern Atlantic Ocean, and parts of the southern Indian Ocean have all experienced record warmth for the year-to-date.

January–October Ranks and Records
(out of 133 years)
Land+0.94 ± 0.21+1.69 ± 0.38Warmest6th2007+1.09+1.96
Ocean+0.44 ± 0.04+0.79 ± 0.07Warmest10th1998+0.54+0.97
Ties: 1997
Land and Ocean+0.58 ± 0.09+1.04 ± 0.16Warmest8th2010+0.67+1.21
Northern Hemisphere
Land+1.04 ± 0.26+1.87 ± 0.47Warmest4th2007+1.22+2.20
Coolest130th1883, 1884-0.72-1.30
Ocean+0.45 ± 0.05+0.81 ± 0.09Warmest8th2005+0.56+1.01
Ties: 2002, 2007
Land and Ocean+0.67 ± 0.15+1.21 ± 0.27Warmest6th2010+0.77+1.39
Southern Hemisphere
Land+0.68 ± 0.13+1.22 ± 0.23Warmest8th2005+0.92+1.66
Ocean+0.45 ± 0.04+0.81 ± 0.07Warmest10th1998+0.57+1.03
Ties: 1997
Land and Ocean+0.48 ± 0.07+0.86 ± 0.13Warmest9th1998+0.62+1.12
Ties: 2001
Land and Ocean+1.04 ± 0.16+1.87 ± 0.29Warmest8th2011+1.39+2.50

The most current data may be accessed via the Global Surface Temperature Anomalies page.

Images of sea surface temperature conditions are available for all weeks during 2012 from the weekly SST page.


The maps below represent precipitation percent of normal (left) and precipitation percentiles (right) based on the GHCN dataset of land surface stations using a base period of 1961–1990. As is typical, precipitation anomalies during October 2012 varied significantly around the world.

  • Western parts of Finland observed precipitation totals that were double the October monthly average. Some stations broke their all-time highest monthly precipitation records for October.

  • Sandy dumped copious rain over Jamaica, Haiti, the Dominican Republic, Cuba, and much of the eastern United States. Sandy also brought blizzard conditions to the Central and Southern Appalachians, shattering all-time U.S. October monthly and single storm snowfall records.

  • October was dry across Australia, with the continent experiencing rainfall that was 48 percent of average for the month. This was the 10th driest October since precipitation records began in 1900. South Australia was fifth driest on record, reporting just 18 percent of average rainfall.

Additional details on flooding and drought events around the world can also be found on the October 2012 Global Hazards page.


Peterson, T.C. and R.S. Vose, 1997: An Overview of the Global Historical Climatology Network Database. Bull. Amer. Meteorol. Soc., 78, 2837-2849.

Quayle, R.G., T.C. Peterson, A.N. Basist, and C. S. Godfrey, 1999: An operational near-real-time global temperature index. Geophys. Res. Lett., 26, 333-335.

Smith, T.M. and R.W. Reynolds, 2005: A global merged land air and sea surface temperature reconstruction based on historical observations (1880-1997), J. Clim., 18, 2021-2036.

Smith et al., 2008, Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880-2006), J. Climate., 21, 2283-2293.

Citing This Report

NOAA National Centers for Environmental Information, Monthly Global Climate Report for October 2012, published online November 2012, retrieved on May 29, 2024 from