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.

Global Highlights

  • The combined average temperature over global land and ocean surfaces for August 2013 tied with 2005 as the fourth highest in the 1880–2013 record, at 0.62°C (1.12°F) above the 20th century average of 15.6°C (60.1°F).
  • The global land surface temperature was 0.77°C (1.39°F) above the 20th century average of 13.8°C (56.9°F), the 11th warmest August on record. For the global oceans, the August average sea surface temperature was 0.57°C (1.03°F) above the 20th century average of 16.4°C (61.4°F), tying with 1998, 2003, 2005, and 2009 as the record highest for August.
  • The combined global land and ocean average surface temperature for the June–August period was 0.62°C (1.12°F) above the 20th century average of 15.6°C (60.1°F), tying with 2009 as the fifth warmest such period on record.
  • The June–August worldwide land surface temperature was 0.85°C (1.53°F) above the 20th century average, the seventh warmest such period on record. The global ocean surface temperature for the same period was 0.53°C (0.95°F) above the 20th century average, the fifth warmest June–August on record.
  • The combined global land and ocean average surface temperature for the year-to-date (January–August) was 0.59°C (1.06°F) above the 20th century average of 14.0°C (57.3°F), tying with 2003 as the sixth warmest such period on record.


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 August 2013 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 August 2013 height and anomaly mapAugust 2013 and June - August 2013 height and anomaly mapJune–August 2013 maps—is generally reflected by areas of positive and negative temperature anomalies at the surface, respectively.


The average temperature across global land and ocean surfaces during August 2013 was 0.62°C (1.12°F) above the 20th century average, tying with 2005 as the fourth highest for August since records began in 1880. This marks the fourth consecutive month (since May 2013) that the monthly global temperature has ranked among the top six warmest for its respective month. During August, warmer-than-average temperatures across most of the world's ocean surfaces contributed to the anomalous warmth. Even with ENSO-neutral conditions holding for the 16th straight month, including below-average temperatures in the eastern equatorial Pacific, the August global ocean temperature tied with 1998, 2003, 2005, and 2009 as record highest for August, at 0.57°C (1.03°F) above the 20th century average. Regionally, the tropical oceans (20°N–20°S) were 12th warmest on record for August, while both the Northern and Southern Hemisphere oceans above 20° latitude (outside the tropics) were record warm, at 0.81°C (1.46°F) and 0.55°C (0.99°F) above their long-term averages, respectively. With respect to specific areas, according to the Land & Ocean Temperature Percentiles map above, part of the Barents Sea in the Arctic region, sections of the western Pacific Ocean, and part of the south central Indian Ocean were record warm for August. Many other regions across all of the oceans were much warmer than average. NOAA's Climate Prediction Center forecasts ENSO-neutral conditions to continue in the central and eastern equatorial Pacific Ocean through the Northern Hemisphere winter 2013/14.

Most of the world's land areas experienced warmer-than-average monthly temperatures, including Australia, northern South America, western North America, Europe, and much of eastern Asia. Far eastern China, part of eastern Russia north of Japan, and part of northeastern South America were record warm for the month. The southeastern United States, Far East Russia, part of South Africa, Paraguay, and Bolivia were cooler than average. No regions of the globe were record cold. Overall, the globally-averaged temperature over land surfaces was the 11th highest for August in the 134-year period of record, at 0.77°C (1.39°F) above the 20th century average.

Select national information is highlighted below:
  • New Zealand reported its warmest August since national records began in 1909, with an average temperature 1.9°C (3.4°F) above the 1971–2000 average.

  • Australia observed its second warmest average and maximum August temperatures since national records began in 1910, at 1.60°C (2.88°F) and 2.60°C (4.68°F) above the 1961–1990 average, respectively. With the exception of the southernmost island state of Tasmania, all states and territories had average temperatures that were among their 10 highest for August.

  • South Korea reported its highest average and maximum August temperatures at 2.2°C (4.0°F) and 2.5°C (4.5°F) above the 1981–2010 average. The country also observed its second highest August minimum temperature in its 41-year period of record, at 1.9°C (3.4°F) above average.
August Ranks and Records
(out of 134 years)
Land+0.77 ± 0.23+1.39 ± 0.41Warmest11th1998+1.00+1.80
Ocean+0.57 ± 0.05+1.03 ± 0.09Warmest1st1998, 2003, 2005, 2009, 2013+0.57+1.03
Coolest134th1910, 1911-0.45-0.81
Ties: 1998, 2003, 2005, 2009
Land and Ocean+0.62 ± 0.12+1.12 ± 0.22Warmest4th1998+0.69+1.24
Ties: 2005
Northern Hemisphere
Land+0.80 ± 0.20+1.44 ± 0.36Warmest9th2010+1.05+1.89
Ties: 1995
Ocean+0.63 ± 0.06+1.13 ± 0.11Warmest3rd2005+0.66+1.19
Ties: 2009
Land and Ocean+0.70 ± 0.15+1.26 ± 0.27Warmest4th2010+0.77+1.39
Southern Hemisphere
Land+0.69 ± 0.12+1.24 ± 0.22Warmest10th2009+1.33+2.39
Ocean+0.52 ± 0.06+0.94 ± 0.11Warmest4th1998+0.57+1.03
Land and Ocean+0.54 ± 0.06+0.97 ± 0.11Warmest6th2009+0.66+1.19
Ties: 2002
Land and Ocean+0.70 ± 0.22+1.26 ± 0.40Warmest5th2003+1.05+1.89
Seasonal (June–August)

June–August (Northern Hemisphere summer / Southern Hemisphere winter) tied with 2009 as the fifth warmest such period across global land and ocean surfaces since records began in 1880, at 0.62°C (1.12°F) above the 20th century average. The tropics (20°N–20°S) were 11th warmest, while the regions above 20° latitude in the Northern and Southern Hemispheres ranked third warmest and record warmest (tied with 2005), respectively.

Globally, the average ocean temperature for June–August was the fifth highest on record for the period, at 0.53°C (0.95°F) above average. As indicated by the Land & Ocean Temperature Percentiles map above, few regions were below average, most notably the eastern equatorial Pacific Ocean and the part of the North Atlantic Ocean near Greenland. Many areas were much warmer than average, with sections of the eastern Atlantic, parts of the south central and southeast Indian Ocean, and parts of the western equatorial and northwestern Pacific Ocean observing record warmth.

The average land surface temperature was seventh highest on record for June–August. The Northern Hemisphere summer was fifth warmest for the period, while the Southern Hemisphere winter temperature was fourth warmest on record. Part of northwestern Russia, southern Japan, parts of southern China, southeastern Australia, part of the southwestern United States, and a region in central Canada were record warm. No region of the world's land areas was record cold or even much cooler than average, as shown by the Percentiles map.

Select national information is highlighted below:
  • Austria observed its sixth warmest June–August since national records began in 1767, at 1.2°C (2.2°F) higher than the 1981–2010 average. In the midst of an extended heat wave that occurred from July 20th to August 10th, a new national record high temperature of 40.5°C (104.9°F) was set in lower German-Altenburg (August 8th). This was the first date a temperature above 40°C (104°F) was observed in Austria. Several other statewide maximum temperature records were also broken during this period.

  • The average temperature for New Zealand during June–August was 1.2°C (2.2°F) above the 1971–2000 average, marking the warmest winter on record for this island nation since records began in 1909.

  • The average maximum temperature across Australia during June–August was 1.42°C (2.56°F) above the 1961–1990 average, the second highest since national records began in 1910. The average minimum temperature was 1.14°C (2.05°F) above average, the sixth highest for the period on record for the country. With the exception of Tasmania and Western Australia, every state and territory had average minimum and maximum temperatures that ranked among their ten highest on record for the period.

  • South Korea had its warmest summer (June–August) on record, with the average and minimum temperatures record high, at 1.8°C (3.2°F) and 2.0°C (3.6°F) higher than the 1981–2010 average, respectively, and the maximum temperature second highest since records began in 1973, at 1.7°C (3.1°F) higher than average.
June–August Ranks and Records
(out of 134 years)
Land+0.85 ± 0.20+1.53 ± 0.36Warmest7th2010+1.01+1.82
Ocean+0.53 ± 0.05+0.95 ± 0.09Warmest5th1998, 2009+0.58+1.04
Land and Ocean+0.62 ± 0.11+1.12 ± 0.20Warmest5th1998+0.69+1.24
Ties: 2009
Northern Hemisphere
Land+0.84 ± 0.18+1.51 ± 0.32Warmest8th2012+1.16+2.09
Ocean+0.60 ± 0.05+1.08 ± 0.09Warmest3rd2005+0.64+1.15
Land and Ocean+0.69 ± 0.15+1.24 ± 0.27Warmest5th2010+0.80+1.44
Ties: 2006
Southern Hemisphere
Land+0.87 ± 0.13+1.57 ± 0.23Warmest4th2005+0.98+1.76
Ocean+0.48 ± 0.05+0.86 ± 0.09Warmest9th1998+0.59+1.06
Ties: 2010, 2012
Land and Ocean+0.54 ± 0.07+0.97 ± 0.13Warmest5th1998+0.65+1.17
Ties: 2002
Land and Ocean+0.96 ± 0.10+1.73 ± 0.18Warmest5th2012+1.03+1.85

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

Year-to-date (January–August)

The globally-averaged temperature across land and ocean surfaces for the first eight months of 2013 (January–August) was 0.59°C (1.06°F) above the 20th century average, tying with 2003 as the sixth warmest January–August on record. The average global land temperature for this period was the seventh warmest on record, at 0.93°C (1.67°F) above the long-term average, while the average global ocean temperature was the eighth warmest in the 134-year period of record, at 0.47°C (0.85°F) above average. ENSO-neutral conditions were present in the eastern and central equatorial Pacific Ocean during the entire year-to-date (this phase began in April 2012). The record warmest January–August (0.70°C / 1.26°F above average) occurred in 2010, when a warm El Niño phase was present during January–April before transitioning to La Niña conditions during the summer. Images of sea surface temperature conditions are available from the weekly SST page

January–August Ranks and Records
(out of 134 years)
Land+0.93 ± 0.22+1.67 ± 0.40Warmest7th2007+1.12+2.02
Coolest128th1885, 1893-0.70-1.26
Ocean+0.47 ± 0.05+0.85 ± 0.09Warmest8th1998+0.57+1.03
Land and Ocean+0.59 ± 0.11+1.06 ± 0.20Warmest6th2010+0.70+1.26
Ties: 2003
Northern Hemisphere
Land+0.95 ± 0.25+1.71 ± 0.45Warmest9th2007+1.28+2.30
Ocean+0.49 ± 0.06+0.88 ± 0.11Warmest5th2010+0.57+1.03
Land and Ocean+0.67 ± 0.15+1.21 ± 0.27Warmest6th2010+0.80+1.44
Coolest129th1893, 1913-0.51-0.92
Ties: 2012
Southern Hemisphere
Land+0.87 ± 0.15+1.57 ± 0.27Warmest4th2005+0.97+1.75
Ocean+0.46 ± 0.05+0.83 ± 0.09Warmest10th1998+0.60+1.08
Land and Ocean+0.52 ± 0.07+0.94 ± 0.13Warmest7th1998+0.65+1.17
Land and Ocean+0.73 ± 0.14+1.31 ± 0.25Warmest16th2011+1.48+2.66

The most current data August be accessed via the Global Surface Temperature Anomalies 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 August 2013 varied significantly around the world. As indicated by the August precipitation percentiles map below, record wetness was observed over part of the central United States and far eastern India. Record dryness was scattered across different parts of the globe, including parts of the north central United States, northern Chile, small sections of Africa and eastern Europe, along with regions in both western and eastern Australia.

  • Very heavy rainfall during August 1st–12th brought 300 mm (12 inches) of rainfall to Far East Russia near the China border, leading to the worst flooding in more than a century in that region.

  • Torrential rainfall from heavy monsoon rains and the effects of Tropical Storm Trami brought major flooding to parts of the Philippines in mid-August. On August 19th, the northern island of Luzon recieved up to 30 mm (more than one inch) of rainfall per hour. Some areas in the capital city of Manila were submerged in up to two meters (6.5 feet) of floodwaters, making streets impassable, according to media reports

  • .
  • Tropical Storm Trami also brought heavy precipitation to Taiwan and China. Although the storm did not make landfall over the country, heavy rains caused major flooding and mudslides in parts of Taiwan. About 700 mm (27.5 inches) of rain fell over Heping District, Taichung City in northern Taiwan over a 48-hour period (August 20th–22nd), according to the Central Weather Bureau. Trami continued on a westward path and became the 12th tropical storm to hit China in 2013, making landfall around Fuqing City in Fujian Province on the 22nd. Heavy rain also fell over Guangdong and Zheijang Provinces. Rains from Trami exacerbated flood conditions brought about from Tropical Cyclone Utor, which had impacted the country the previous week.

  • Germany observed its driest summer since 2003, with just 79 percent of average rainfall.
  • During the Asian Southwest Monsoon season, which occurs annually during June–September, India as a whole received 110 percent of the 1951–2000 average from June 1st through August 31st. Among the four main geographical regions, Central India received 128 percent of average rainfall, while Northeast India received just 72 percent of average rainfall during this period.


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 August 2013, published online September 2013, retrieved on July 19, 2024 from