Significant Climate Anomalies and Events in 2005

PLEASE NOTE: The ranks and temperature anomalies in this report represent the values known at the time the report was issued. The actual ranks will change as subsequent years are added to the dataset. The anomalies themselves may change slightly as missing or erroneous data is resolved. Also, in 2009, NCDC switched to ERSST version 3b (from version 2) as a component of its global surface temperature dataset. Because the versions have slightly different methodologies, the calculated temperature anomalies will differ slightly. For more information about this switch please see the Global Surface Temperature Anomalies FAQ .

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Global Temperatures

The 2005 global temperature was statistically indistinguishable from the standing record set in 1998. One data set, in use at NCDC since the late 1990s, produced a global annual temperature for 2005 that was slightly below 1998 (below left). An improved data set, which incorporates innovative algorithms that better account for factors such as changes in spatial coverage and evolving observing methods, results in 2005 being slightly warmer than 1998. (below right)

2005 Annual Timeseries plot for dataset in use since late 1990s
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2005 Annual Timeseries plot for improved dataset
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The time series on the left shows that the global annual temperature for combined land and ocean surfaces in 2005 was 0.58°C (1.04°F) above average, ranking 2nd. The time series from the improved Smith & Reynolds data set on the right provides a global temperature of 0.62°C (1.12°F) above the 1880-2004 mean, while 1998 was 0.59°C (1.06°F) above average. This data set also provides for the calculation of uncertainties in global temperature attributable to factors such as changes in spatial coverage and evolving observing methods. The range of uncertainty is shown for each year with the uncertainty bounds smaller in more recent years as sampling and random errors decrease with time due to improved coverage and better instruments and measurement techniques.

When calculating global temperatures, NCDC scientists, as well as those at NASA and in the United Kingdom, use methods that address areas of the globe with sparse observations or measurement biases. The various methodologies result in very small differences (on the order of a few hundredths of a degree Celsius) between the global temperature estimates, and these differences can affect individual yearly rankings. Although the ranking of individual years may differ slightly from data set to data set, all records indicate that during the past century, global surface temperatures have increased at a rate near 0.6°C/century (1.1°F/century), but the trend has been three times larger since 1976, with some of the largest temperature increases occurring in the high latitudes.

The widespread anomalous warmth in 2005 is evident in the map to the lower left. Temperature anomalies in 1998 are shown in the map to the right.

Current year's Blended Land and Ocean Surface Temperature Dot map
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1998 Blended Land and Ocean surface Temperature Dot map
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The 1880-2004 average combined land and ocean annual temperature is 13.9°C (56.9°F), the annually averaged land temperature for the same period is 8.5°C (47.3°F), and the long-term annually averaged sea surface temperature is 16.1°C (60.9°F).

Regional Temperatures

Global Temperature land surface dotmap
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Warmer than average conditions occurred throughout most land areas of the world in 2005. The largest anomalies were widespread throughout high latitude regions of the Northern Hemisphere that include much of Russia, Scandinavia, Canada and Alaska. Temperatures in these regions were 3-5°C (5.4-9.0°F) above the 1961-1990 average. There were no widespread areas of negative anomalies.

The map to the left was created using data from the Global Historical Climatology Network (GHCN), a network of more than 7,000 land surface observing stations.

Notable temperature extremes in 2005 include a severe heat wave that gripped the southwestern United States during early to mid-July. Maximum temperatures above 40°C (104°F) affected parts of Nevada, California, Arizona and southern Utah. Numerous temperature records were set around the region. Las Vegas, NV tied their all-time record high temperature of 47.2°C (117°F) on the 19th. Death Valley had 7 consecutive days (July 14-20) with high temperatures equal to or above 51.7°C (125°F). Across Australia, exceptionally warm and dry weather prevailed during March-May 2005. The Australian mean temperature during March-May was 1.62°C (2.92°F) above the long-term average, which is the warmest on record.

In February, extremely cold temperatures affected much of the Balkan region for the first half of the month. In Sevlievo, Bulgaria, a 50-year temperature record was broken when temperatures reached as low as -34°C (-29°F). For more information on temperature extremes during 2005 see the annual report of Significant Events

Additional information on other notable weather events can be found in the Significant Events section of this report.

Global Precipitation

Global Precipitation Anomalies graph
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Global precipitation in 2005 was near the 1961-1990 average. Regionally drier than average conditions were widespread across eastern Australia, parts of Western Europe, and the U.S. Mississippi Valley and southern Great Plains region. In Australia, Victoria and South Australia experienced the second-driest May on record. In the U.S., Chicago's O'Hare International Airport had the driest spring, summer and fall on record with a total of 420 mm (16.54 inches).

Little to no rain has fallen in Brazil since December 2004. Rainfall was much below average in the Amazon Basin in 2005, producing the worst drought in 60 years in some parts of the region and resulting in the lowest water levels in at least 30 years along the world's second longest river. Across southeastern Africa, long-term drought affected parts of Mozambique, southern Malawi and Zimbabwe. For further information on precipitation events during 2005, see the annual report of Significant Events.

In contrast, several regions of the globe experienced heavy precipitation during 2005. India monsoon rainfall was near normal (98 percent). In July, a new 24-hour rainfall event record was established on the 26th in the city of Mumbai, when over 944 mm (37 inches) of rain fell. A winter storm brought heavy snowfall to much of the northeastern U.S. Boston recorded it's snowiest month on record in January with 1095 mm (43.1 inches) of snow. In Colombia, heavy rains in October and November triggered floods and landslides. In Saudi Arabia, heavy rains during January, produced some of the worst flooding in 20 years in the city of Medina. In August, heavy rainfall affected areas of central and eastern Europe with flooding reported in sections of Romania, Hungary and Macedonia. Farther to the west, flooding also affected areas of Germany, Austria and Switzerland. For more information about precipitation extremes during 2005, see the annual report of Significant Events.

Additional information on other notable weather events can be found in the Significant Events section of this report.

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NOAA's National Climatic Data Center is the world's largest active archive of weather data. The preliminary temperature and precipitation rankings are available from the center by calling: 828-271-4800.

NOAA works closely with the academic and science communities on climate-related research projects to increase the understanding of El Niño and improve forecasting techniques. NOAA's Climate Prediction Center monitors, analyzes and predicts climate events ranging from weeks to seasons for the nation. NOAA also operates the network of data buoys and satellites that provide vital information about the ocean waters, and initiates research projects to improve future climate forecasts. This is a break in the document


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.

Citing This Report

NOAA National Centers for Environmental Information, Monthly Global Climate Report for Annual 2005, published online January 2006, retrieved on April 23, 2024 from