State of the Climate
Global Analysis
October 2011

National Oceanic and Atmospheric Administration

National Climatic Data Center

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Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective November 2011, the GHCN-M version 3.1.0 dataset of monthly mean temperature replaced the GHCN-M version 3 monthly mean temperature dataset. Beginning with the October 2011 Global monthly State of the Climate Report, GHCN-M version 3.1.0 is used for NCDC climate monitoring activities, including calculation of global land surface temperature anomalies and trends.

For more information about this newest version, please see the Modifications to Pairwise Homogeneity Adjustment software to address coding errors and improve run-time efficiency.

October 2011 Selected Climate
Anomalies and Events Map

Global Highlights

The combined global land and ocean average surface temperature for October 2011 was the eighth warmest on record at 14.58°C (58.14°F), which is 0.58°C (1.04°F) above the 20^th century average of 14.0°C (57.1°F). The margin of error associated with this temperature is +/- 0.07°C (0.13°F).
Separately, the global land surface temperature was 1.10°C (1.98°F) above the 20^th century average of 9.3°C (48.7°F), making this the second warmest October on record. The margin of error is +/- 0.11°C (0.20°F). Warmer-than-average conditions occurred across Alaska, Canada, most of Europe and Russia, and Mongolia. Cooler-than-average regions included the southeastern United States, most of southern and western South America, parts of Algeria and Libya, part of Eastern Europe, and far southeast Asia.
Separately, the global land surface temperature was 1.10°C (1.98°F) above the 20^th century average of 9.3°C (48.7°F), making this the second warmest October on record. The margin of error is +/- 0.11°C (0.20°F).
The October global ocean surface temperature was 0.39°C (0.70°F) above the 20^th century average of 15.9°C (60.6°F), making it the 11^th warmest October on record. The margin of error is +/- 0.04°C (0.07°F). The warmth was most pronounced across the north central and northwest Pacific, the northeast Atlantic, and portions of the mid-latitude Southern oceans..
The October global ocean surface temperature was 0.39°C (0.70°F) above the 20^th century average of 15.9°C (60.6°F), making it the 11^th warmest October on record. The margin of error is +/- 0.04°C (0.07°F).
The United Kingdom marked its warmest October since 2006 and sixth warmest in the last 100 years, at 1.5°C (2.7°F) above the 1971–2000 average.
Spain had its warmest October since 1990 for the and fifth warmest over the past 50 years, at 1.8°C (3.2°F).
The combined global land and ocean average surface temperature for the January – October period was 0.53°C (0.95°F) above the 20^th century average of 14.0°C (57.4°F), making it the 10^th warmest such period on record. The margin of error is +/- 0.09°C (0.16°F).
The January – October worldwide land surface temperature was 0.85°C (1.53°F) above the 20^th century average — the sixth warmest such period on record. The margin of error is +/- 0.19°C (0.34°F). The global ocean surface temperature for the year to date was 0.41°C (0.74°F) above the 20th century average and was the 12^th warmest such period on record. The margin of error is +/- 0.04°C (0.07°F).
La Niña conditions strengthened during October 2011. According to NOAA's Climate Prediction Center, La Niña is expected to continue through the Northern Hemisphere winter 2011/12.
The average Arctic sea ice extent during October was 23.5 percent below average, ranking as the second smallest October extent since satellite records began in 1979. The extent was 2.19 million square kilometers (846,000 square miles) below average and 330,000 square kilometers (127,000 square miles) above the record low October extent set in 2007.
On the opposite pole, the October Antarctic monthly average extent was 1.2 percent above the 1979–2000 average, the 12^th largest on record.
Despite a record-breaking snowstorm in the US Northeast, Northern Hemisphere snow cover extent during October was below average, and ranked as the 15th smallest October snow cover extent in the 44-year period of record. The North America and Eurasian land areas both had below-average snow cover during the month.

Please Note: The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. Effective with the October 2009 State of the Climate Report, NCDC transitioned to the new version (version 3b) of the extended reconstructed sea surface temperature (ERSST) dataset. ERSST.v3b is an improved extended SST reconstruction over version 2. For more information about the differences between ERSST.v3b and ERSST.v2 and to access the most current data, please visit NCDC's Global Surface Temperature Anomalies page.

Introduction

Temperature anomalies for October 2011 are shown on the dot maps below. The dot map on the left provides a spatial representation of anomalies calculated from the Global Historical Climatology Network (GHCN) dataset of land surface stations using a 1961–1990 base period. The dot map on the right is a product of a merged land surface and sea surface temperature (SST) anomaly analysis developed by Smith et al. (2008). For the merged land surface and SST analysis, temperature anomalies with respect to the 1971–2000 average 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.

October

October 2011 was much warmer than normal compared with previous Octobers. On average, land areas across the Northern Hemisphere—where the majority of the Earth's land mass is located—were the warmest on record for the month, at 1.29°C (2.32°F) above the 20^th century average. The warmth was especially pronounced across Alaska, Canada, Mongolia, and most of Russia and Europe. According to the UK Met Office, the United Kingdom marked its warmest October since 2006 and eighth warmest in the last 100 years, at 2.0°C (3.6°F) above the 1971–2000 average. Norway also reported its eighth warmest October, at 1.8°C (2.6°F) above normal, with records dating back to 1900.The dot maps below show much of central and northern Russia with average temperatures more than 5°C (9°F) above average. Temperatures in the Southern Hemisphere were also above average, ranking 16^th warmest on record. However, most of southern and western South America was cooler than average. According to the Argentina Meteorological Service (Servicio Meteorológico Nacional), several locations in Argentina experienced their coolest October in five decades. Globally, the average October land surface temperature was second warmest on record, at 1.10°C (1.98°F) above average.

La Niña conditions continued to strengthen in the eastern central Pacific Ocean during October, according to NOAA's Climate Prediction Center. Globally, the average October sea surface temperature was 13^th warmest on record, with similar monthly average temperature anomalies in both the Northern and Southern Hemisphere oceans. While it was cooler than normal in the region of the Pacific where ENSO conditions are measured and also in the northeast Pacific, it was notably warmer than normal across the north central and northwest Pacific, the northeast Atlantic, and portions of the mid-latitude Southern oceans.

Overall, the combined global average land and ocean temperature ranked as the eighth warmest October in the 132-year period of record.

October Land Surface Temperature Anomalies in degree Celsius

October Land Surface Temperature
Anomalies in degrees Celsius

October Blended Land and Sea Surface
Temperature Anomalies in degrees Celsius

Year-to-date (January–October)

La Niña conditions have been present during all months to-date in 2011, with the exception of May, June, and July, when ENSO-neutral conditions briefly returned. These conditions impacted temperatures around the globe, making the January–October combined global land and ocean temperature the 10^th warmest such period on record and the coolest since 2008, at 0.53°C (0.95°F) above average. The January–October 2011 map of temperature anomalies shows regions with anomalously warm and anomalously cool temperatures. Over land, the most anomalous warmth enveloped nearly all of central and western Russia. Few regions were cooler than normal, most notably much of northern Australia the north central and northwest United States, and southwest Canada. Overall, the global land surface temperature anomaly (0.85°C / 1.53°F) was more than twice as high as the global sea surface temperature anomaly (0.41°C / 0.74°F) for this period, ranking as 6^th warmest and 12^th warmest, respectively.

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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 2011 map, respectively) are generally reflected by areas of positive and negative temperature anomalies at the surface, respectively. For other Global products, please see the Climate Monitoring Global Products page.

Images of sea surface temperature anomalies are available for each week from 2004 to present on the weekly SST page.

Temperature Rankings and Graphics

Current Month | Year-to-date

October	Anomaly		Rank (out of 132 years)	Records
October	°C	°F	Rank (out of 132 years)	Year(s)	°C	°F
Global
Land	+1.10 ± 0.11	+1.98 ± 0.20	2^nd Warmest	Warmest: 2005	+1.14	+2.05
Land	+1.10 ± 0.11	+1.98 ± 0.20	131^st Coolest	Coolest: 1976	-0.88	-1.58
Ocean	+0.39 ± 0.04	+0.70 ± 0.07	11^th Warmest	Warmest: 2003	+0.58	+1.04
	+0.39 ± 0.04	+0.70 ± 0.07	122^nd Coolest	Coolest: 1909	-0.47	-0.85
	Ties: 1998
Land and Ocean	+0.58 ± 0.07	+1.04 ± 0.13	8^th Warmest	Warmest: 2003	+0.72	+1.30
Land and Ocean	+0.58 ± 0.07	+1.04 ± 0.13	125^th Coolest	Coolest: 1912	-0.54	-0.97
Northern Hemisphere
Land	+1.29 ± 0.11	+2.32 ± 0.20	1^st Warmest	Warmest: 2003	+1.25	+2.25
Land	+1.29 ± 0.11	+2.32 ± 0.20	132^nd Coolest	Coolest: 1912	-1.15	-2.07
Ocean	+0.40 ± 0.04	+0.72 ± 0.07	12^th Warmest	Warmest: 2003, 2006	+0.65	+1.17
Ocean	+0.40 ± 0.04	+0.72 ± 0.07	121^st Coolest	Coolest: 1912	-0.50	-0.90
Land and Ocean	+0.73 ± 0.08	+1.31 ± 0.14	5^th Warmest	Warmest: 2003	+0.88	+1.58
Land and Ocean	+0.73 ± 0.08	+1.31 ± 0.14	128^th Coolest	Coolest: 1912	-0.74	-1.33
Southern Hemisphere
Land	+0.58 ± 0.17	+1.04 ± 0.31	16^th Warmest	Warmest: 2006	+1.15	+2.07
Land	+0.58 ± 0.17	+1.04 ± 0.31	117^th Coolest	Coolest: 1910	-0.74	-1.33
Ocean	+0.39 ± 0.04	+0.70 ± 0.07	13^th Warmest	Warmest: 1997	+0.59	+1.06
Ocean	+0.39 ± 0.04	+0.70 ± 0.07	120^th Coolest	Coolest: 1910	-0.46	-0.83
Land and Ocean	+0.42 ± 0.06	+0.76 ± 0.11	12^th Warmest	Warmest: 1997	+0.62	+1.12
	+0.42 ± 0.06	+0.76 ± 0.11	121^st Coolest	Coolest: 1910	-0.51	-0.92
	Ties: 1996, 2001, 2007

October Global Land and Ocean plot

October Global Hemisphere plot

January–October	Anomaly		Rank (out of 132 years)	Records
January–October	°C	°F	Rank (out of 132 years)	Year(s)	°C	°F
Global
Land	+0.85 ± 0.19	+1.53 ± 0.34	6^th Warmest	Warmest: 2007	+1.06	+1.91
	+0.85 ± 0.19	+1.53 ± 0.34	127^th Coolest	Coolest: 1893	-0.62	-1.12
	Ties: 2009
Ocean	+0.41 ± 0.04	+0.74 ± 0.07	12^th Warmest	Warmest: 1998	+0.54	+0.97
Ocean	+0.41 ± 0.04	+0.74 ± 0.07	121^st Coolest	Coolest: 1911	-0.47	-0.85
Land and Ocean	+0.53 ± 0.09	+0.95 ± 0.16	10^th Warmest	Warmest: 2010	+0.66	+1.19
	+0.53 ± 0.09	+0.95 ± 0.16	123^rd Coolest	Coolest: 1911	-0.45	-0.81
	Ties: 2001
Northern Hemisphere
Land	+0.96 ± 0.20	+1.73 ± 0.36	5^th Warmest	Warmest: 2007	+1.19	+2.14
Land	+0.96 ± 0.20	+1.73 ± 0.36	128^th Coolest	Coolest: 1893	-0.67	-1.21
Ocean	+0.40 ± 0.04	+0.72 ± 0.07	12^th Warmest	Warmest: 2005	+0.56	+1.01
	+0.40 ± 0.04	+0.72 ± 0.07	121^st Coolest	Coolest: -0.47	-0.85	0.05
	Ties: 2008
Land and Ocean	+0.61 ± 0.13	+1.10 ± 0.23	10^th Warmest	Warmest: 2010	+0.75	+1.35
Land and Ocean	+0.61 ± 0.13	+1.10 ± 0.23	123^rd Coolest	Coolest: -0.47	-0.85	0.06
Southern Hemisphere
Land	+0.57 ± 0.15	+1.03 ± 0.27	12^th Warmest	Warmest: 2005	+0.92	+1.66
	+0.57 ± 0.15	+1.03 ± 0.27	121^st Coolest	Coolest: 1917	-0.73	-1.31
	Ties: 1983, 2008
Ocean	+0.43 ± 0.04	+0.77 ± 0.07	11^th Warmest	Warmest: 1998	+0.56	+1.01
Ocean	+0.43 ± 0.04	+0.77 ± 0.07	122^nd Coolest	Coolest: 1911	-0.51	-0.92
Land and Ocean	+0.45 ± 0.07	+0.81 ± 0.13	12^th Warmest	Warmest: 1998	+0.62	+1.12
Land and Ocean	+0.45 ± 0.07	+0.81 ± 0.13	121^st Coolest	Coolest: 1911	-0.52	-0.94

January-October Global Land and Ocean plot

January-October Global Hemisphere plot

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

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Precipitation

The maps below represent anomaly values based on the GHCN dataset of land surface stations using a base period of 1961–1990. Precipitation anomalies on a month-to-month basis are often highly variable across the globe and even within regions.

There were several areas across the globe with anomalous wetness or anomalous dryness during October. With the end of the South Asian monsoon season, India and Bangladesh observed drier-than-normal conditions. It was also abnormally dry in northeastern China, eastern Australia, the central United States and much of Canada. An unusually wet monsoon season brought devastating floods to Thailand. Seasonal rains brought wetter-than-normal conditions to Algeria and Ethiopia. The remnants of Hurricane Rina affected south Florida and brought heavy precipitation in the form of snowfall to the northeast United States. Other regions that experienced above-average rainfall included eastern South America, the northwest United States, Western Australia, and Pakistan.

October 2011 Precipitation Anomalies in Millimeters

October 2011 Precipitation Percent Departures

Rainfall across Australia was 52 percent above average, making this month the 17^th wettest October in its 112-year period of record, according to Australia's Bureau of Meteorology. The wetness was due largely to well-above average rainfall in the tropical north and western half of the country. Western Australia saw average rainfall more than two times higher than normal, making this October its third wettest on record and wettest since 1975. Weak La Niña conditions were present in October, and La Niña is associated with heavier-than-average precipitation in Australia.

Additional details on extreme climate events and flooding and drought conditions can also be found on the October 2011 Global Hazards page.

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References

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.

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Citing This Report

NOAA National Climatic Data Center, State of the Climate: Global Analysis for October 2011, published online November 2011, retrieved on May 24, 2012 from http://www.ncdc.noaa.gov/sotc/global/2011/oct.