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.
- The combined average temperature over global land and ocean surfaces for July 2013 was the sixth highest on record, at 0.61°C (1.10°F) above the 20th century average of 15.8°C (60.4°F).
- The global land surface temperature was 0.78°C (1.40°F) above the 20th century average of 14.3°C (57.8°F), marking the eighth warmest July on record. For the ocean, the July global sea surface temperature was 0.54°C (0.97°F) above the 20th century average of 16.4°C (61.5°F), the fifth warmest July on record.
- The combined global land and ocean average surface temperature for the January–July period (year-to-date) was 0.59°C (1.06°F) above the 20th century average of 13.8°C (56.9°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 July 2013 Global State of the Climate report includes percentile maps that complement the information provided by the anomaly maps. These 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-to-date 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 July 2013 map—is generally reflected by areas of positive and negative temperature anomalies at the surface, respectively.
The average global temperature across the world's land and ocean surfaces for July 2013 was 0.61°C (1.10°F) above the 20th century average of 15.8°C (60.4°F), making this the sixth warmest July since records began in 1880. This marks the 341st consecutive month, since February 1985, that the global monthly temperature has been higher than the long-term average for its respective month. Nine of the ten warmest Julys on record have occurred since the beginning of the 21st century (July 1998 is currently the record warmest).
Most of the world's land surfaces were warmer than average during July, with northern South America, the western and northeastern United States, much of Africa, western and central Europe, parts of southern Asia, and most of Australia classified as much warmer than average, as indicated by the Land and Ocean Temperature Percentiles map above. Parts of the central and southeastern United States, small regions across northern Canada, eastern Greenland, and parts of Mongolia and eastern Russia were cooler than average. Far northwestern Canada and part of the eastern United States were much cooler than their long-term averages. Overall, the globally-averaged land surface temperature was the eighth warmest July on record, at 0.78°C (1.40°F) above the 20th century average. The Northern Hemisphere tied with 2008 as 10th warmest, while the Southern Hemisphere was second highest for July, behind only 1998.Select national information is highlighted below:
- The national July temperature for Australia was 1.46°C (2.63°F) above the 1961–1990 average, marking the third warmest July since national records began in 1901. The July maximum temperature was the third highest at 1.52°C (2.74°) above average, while the minimum temperature was eighth highest. With the exception of Western Australia, every state and territory had an average July temperature that ranked among their seven highest on record. Tasmania reported a record high state-wide maximum temperature that was 1.28°C (2.30°F) higher than average, breaking the previous record set in 1950 and tied in 1993. No state or territory had maximum or minimum temperatures below their long-term averages.
- New Zealand observed its fourth warmest July since national records began in 1909, with a temperature that was 1.2°C (2.2°F) higher than the 1971–2000 average. Many locations around Otago and Canterbury on the South Island had a record warm July.
- Spain had its fifth warmest July since national records began in 1961, with a temperature that was 1.6°C (2.9°F) above the 1971–2000 average. The northern regions observed the highest anomalies, with some areas up to 3°C (5°F) above average.
- It was the third warmest July across the United Kingdom since records began in 1910, at 1.9°C (3.4°F) above the 1981–2010 average. The "most notable heat wave since 2006" contributed to the warmth, according to the UK Met Office. Provisionally, it was the warmest July and second warmest month of any month on record (behind August 1995) for Northern Ireland.
- With records dating back to 1767, Austria reported its second warmest July, tied with July 1983 and behind only 2006, with the nationally-averaged temperature 2.2°C (4.0°F) above the 1981–2010 average. Upper Austria and Salzburg each set new state maximum temperatures on July 28th.
- The average July temperature across South Korea was the fourth warmest in the country's 41-year period of record, at 1.8°C (3.2°F) above the 1981–2010 average. The July minimum temperature was second highest on record for the month, at 2.1°C (3.8°F) above average.
- July was warmer than average across nearly all of Japan. According to the Japan Meteorological Agency, Western Japan was significantly warmer than average, with a regionally-averaged July temperature that was 1.6°C (2.9°F) above the 1981–2010 average.
The globally-averaged ocean temperature was the fifth highest for July in the 134-year period of record, at 0.54°C (0.97°F) above the 20th century average. This marks the warmest July for the oceans since July 2009, when the last El Niño phase on record was beginning. During July 2013, conditions in the eastern and equatorial Pacific Ocean, where ENSO conditions are monitored via sea surface temperature observations, remained ENSO neutral, with near-average sea surface temperatures across the central and east-central equatorial Pacific and below-average sea surface temperatures in the eastern equatorial Pacific. Neutral conditions, with some temperature variation within the defined range (less than plus or minus 0.5°C / 0.9°F of average), have persisted since spring 2012. According to NOAA's Climate Prediction Center, ENSO neutral conditions are expected to continue into the Northern Hemisphere fall 2013. In other parts of the global oceans, many regions were much warmer than average, with part of the northeastern Atlantic off the coast of North America, sections of the southern Indian Ocean, and various regions in the western Pacific observing record warmth, as indicated on the Land and Ocean Temperature Percentiles map above. The far eastern equatorial Pacific Ocean off the coast of northern South America was the only region of the oceans that was much cooler than average for the month. Images of sea surface temperature conditions are available for all weeks during 2013 from the weekly SST page.
(out of 134 years)
|Land||+0.78 ± 0.18||+1.40 ± 0.32||Warmest||8th||1998||+1.10||+1.98|
|Ocean||+0.54 ± 0.05||+0.97 ± 0.09||Warmest||5th||2009||+0.59||+1.06|
|Land and Ocean||+0.61 ± 0.12||+1.10 ± 0.22||Warmest||6th||1998||+0.73||+1.31|
|Land||+0.70 ± 0.16||+1.26 ± 0.29||Warmest||10th||2012||+1.25||+2.25|
|Ocean||+0.62 ± 0.04||+1.12 ± 0.07||Warmest||3rd||2005||+0.65||+1.17|
|Land and Ocean||+0.65 ± 0.15||+1.17 ± 0.27||Warmest||7th||2010||+0.82||+1.48|
|Land||+0.99 ± 0.12||+1.78 ± 0.22||Warmest||2nd||1998||+1.04||+1.87|
|Ocean||+0.48 ± 0.06||+0.86 ± 0.11||Warmest||7th||1998||+0.60||+1.08|
|Ties: 2006, 2010, 2011, 2012|
|Land and Ocean||+0.57 ± 0.08||+1.03 ± 0.14||Warmest||3rd||1998||+0.68||+1.22|
|Land and Ocean||+0.74 ± 0.09||+1.33 ± 0.16||Warmest||10th||2010||+1.23||+2.21|
The most current data may be accessed via the Global Surface Temperature Anomalies page.
With ENSO-neutral conditions present across the central and eastern equatorial Pacific Ocean for the entire period, the globally-averaged combined land and ocean temperature for the first seven months of 2013 (January–July) was 0.59°C (1.06°F) higher than the 20th century average, tying with 2003 as the sixth warmest such period on record. The global land surface temperature was also the sixth warmest on record. The Northern Hemisphere land areas were eighth warmest on average, while the Southern Hemisphere land was third warmest. In this region, much of Australia, along with part of southern Chile and central Namibia, were record warm, as indicated by the Land & Ocean Temperature Percentiles map above. Around the globe, only land surfaces across much of the United Kingdom and parts the central and southeastern United States were cooler than average for the January–July period. For the global oceans, the average January–July temperature was 0.45°C (0.81°F) above average, the eighth warmest such period on record. It was much warmer than average across the equatorial waters of the Atlantic, Indian, and western Pacific Oceans, along with waters surrounding most of Australia and the far northeastern Atlantic extending into the Arctic Seas.
(out of 134 years)
|Land||+0.96 ± 0.21||+1.73 ± 0.38||Warmest||6th||2007||+1.17||+2.11|
|Ocean||+0.45 ± 0.05||+0.81 ± 0.09||Warmest||8th||1998||+0.57||+1.03|
|Land and Ocean||+0.59 ± 0.11||+1.06 ± 0.20||Warmest||6th||2010||+0.71||+1.28|
|Land||+0.97 ± 0.24||+1.75 ± 0.43||Warmest||8th||2007||+1.32||+2.38|
|Ocean||+0.47 ± 0.06||+0.85 ± 0.11||Warmest||5th||2010||+0.56||+1.01|
|Land and Ocean||+0.66 ± 0.15||+1.19 ± 0.27||Warmest||6th||2010||+0.80||+1.44|
|Land||+0.94 ± 0.15||+1.69 ± 0.27||Warmest||3rd||2010||+1.01||+1.82|
|Ocean||+0.45 ± 0.05||+0.81 ± 0.09||Warmest||10th||1998||+0.60||+1.08|
|Ties: 2007, 2011|
|Land and Ocean||+0.53 ± 0.07||+0.95 ± 0.13||Warmest||7th||1998||+0.66||+1.19|
|Land and Ocean||+0.70 ± 0.16||+1.26 ± 0.29||Warmest||21st||2011||+1.54||+2.77|
The most current data may 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 July 2013 varied significantly around the world. As indicated by the July precipitation percentiles map below, much of the eastern and central United States, India, southeastern Asia, and parts of eastern Russia were wetter or much wetter than average during July. Record dryness was present among regions that included part of central Europe, eastern Turkey, some scattered regions in west Africa, east central Brazil, and northern coastal Chile.
- The United Kingdom had its driest July since 2006, with rainfall 82 percent of the 1981–2010 average. South-west England, East Anglia, and north-west Scotland were among the driest regions during the month.
- Austria observed its driest July since national records began in 1858, with just 35 percent of the 1981–2010 average precipitation. Several regions only received 5 to 20 percent of their typical July rainfall.
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.