Use the form below to access monthly reports.
The data presented in this report are preliminary. Ranks and anomalies may change as more complete data are received and processed. The most current data may be accessed via the Global Surface Temperature Anomalies page.
Temperature anomalies for March-May 2008 and May 2008 are shown on the dot maps below. The dot maps, below left, provide a spatial representation of anomalies calculated from the Global Historical Climatology Network (GHCN) data set of land surface stations using a 1961-1990 base period. The dot maps, below right, are a product of a merged land surface and sea surface temperature anomaly analysis developed by Smith and Reynolds (2005). Temperature anomalies with respect to the 1961-1990 mean for land and ocean are analyzed separately and then merged to form the global analysis. Additional information on this product is available.
Anomalously warm temperatures covered much of the global land throughout the first five months of the year. January-May 2008 had cooler-than-average temperatures across eastern Australia and parts of the north-central and western contiguous U.S. The year-to-date map of temperature anomalies shows the presence of warmer-than-average temperatures across Mexico, Europe, Asia, central and western Australia, the northeastern and southern continental U.S., and most of Africa, Alaska, Brazil, and southern Chile and Argentina. The sea surface temperatures (SSTs) were warmer than average across the Atlantic, western North Pacific, and most of the Indian oceans. Cooler-than-average SSTs were present across the equatorial Pacific Ocean and along the western coast of North America and most of the southern oceans.
During the boreal spring, temperatures were above average in Europe, Asia, Mexico, the southwestern and south-central contiguous U.S., southern and western Australia, northwestern Africa, and parts of Alaska and eastern Brazil. Cooler-than-average conditions occurred across eastern Australia and most of the northern half of the continental U.S. As shown in the maps below, temperatures across Europe and most of Asia were 1-5°C (2-9°F) above the 1961-1990 mean. The warm conditions that engulfed Eurasia during the spring were associated with the lowest recorded snow cover extent for Eurasia and the third least snow cover extent on record for the Northern Hemisphere.
During May, above-average temperatures were observed across Alaska, Mexico, British Isles, central Europe, northwestern and southern Africa, the northwestern and south-central contiguous U.S., northern Canada, and most of Asia. Meanwhile, cooler-than-average conditions were present across Finland, Thailand, the northeastern and north-central continental U.S., and parts of Argentina, western Russia, the eastern half of Mongolia, and northern and northeastern Australia.
May SSTs were warmer than average in the Atlantic and parts of the South Indian and northwestern Pacific oceans. Cooler-than-average conditions were present in parts of the southern oceans, the central equatorial Pacific, and parts of the northeastern Pacific oceans. SSTs warmed across the Niño 3.4 and Niño 4 regions during May, but the anomalies remained below average. Please see the latest ENSO discussion for additional information.
The mean 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 March-May 2008 map and the May map) are generally reflected by areas of positive and negative temperature anomalies at the surface, respectively. For other Global products see the Climate Monitoring Global Products page.
Images of sea surface temperature conditions are available for all weeks during 2008 at the weekly SST page.
Current Month / Seasonal / Year-to-date
Effective with the February 2006 report, NCDC transitioned from the use of the Operational Global Surface Temperature Index (Quayle et al. 1999) to the blended land and ocean dataset developed by Smith and Reynolds (2005). The differences between the two methods are discussed in Smith et al. (2005).
The combined global land and ocean surface temperature was the eighth warmest on record in May and the seventh warmest on record for boreal spring (March-May). Spring 2008 global land temperatures tied with 2000 as the third warmest spring since records began in 1880. Meanwhile, the Northern Hemisphere combined land and ocean, as well as land only, had their third warmest spring on record.
| May | Anomaly | Rank | Warmest (or Next Warmest) Year on Record |
|---|---|---|---|
GlobalLandOcean Land and Ocean |
+0.70°C (+1.26°F) +0.36°C (+0.65°F) +0.45°C (+0.81°F) |
7th warmest 10th warmest 8th warmest |
2007 (+0.96°C/1.73°F) 1998 (+0.54°C/0.97°F) 1998 (+0.62°C/1.12°F) |
Northern HemisphereLandOcean Land and Ocean |
+0.79°C (+1.42°F) +0.38°C (+0.68°F) +0.53°C (+0.95°F) |
8th warmest 8th warmest 8th warmest |
2007 (+1.20°C/2.16°F) 2005 (+0.60°C/1.08°F) 2005 (+0.74°C/1.33°F) |
Southern HemisphereLandOcean Land and Ocean |
+0.41°C (+0.74°F) +0.34°C (+0.61°F) +0.35°C (+0.63°F) |
18th warmest 15th warmest 11th warmest |
2002 (+0.98°C/1.76°F) 1998 (+0.58°C/1.04°F) 1998 (+0.61°C/1.10°F) |
| March-May | Anomaly | Rank | Warmest (or Next Warmest) Year on Record |
|---|---|---|---|
GlobalLandOcean Land and Ocean |
+1.04°C (+1.87°F) +0.33°C (+0.59°F) +0.52°C (+0.94°F) |
3rd warmest 10th warmest 7th warmest |
2007 (+1.17°C/2.11°F) 1998 (+0.53°C/0.95°F) 2005 (+0.65°C/1.17°F) |
Northern HemisphereLandOcean Land and Ocean |
+1.28°C (+2.30°F) +0.34°C (+0.61°F) +0.69°C (+1.24°F) |
3rd warmest 8th warmest 3rd warmest |
2000 (+1.36°C/2.45°F) 2005 (+0.52°C/0.94°F) 2007 (+0.77°C/1.39°F) |
Southern HemisphereLandOcean Land and Ocean |
+0.27°C (+0.49°F) +0.33°C (+0.59°F) +0.32°C (+0.58°F) |
25th warmest 19th warmest 20th warmest |
2005 (+0.96°C/1.73°F) 1998 (+0.57°C/1.03°F) 1998 (+0.61°C/1.10°F) |
| January-May | Anomaly | Rank | Warmest (or Next Warmest) Year on Record |
|---|---|---|---|
GlobalLandOcean Land and Ocean |
+0.75°C (+1.35°F) +0.31°C (+0.56°F) +0.42°C (+0.76°F) |
12th warmest 10th warmest 12th warmest |
2007 (+1.28°C/2.30°F) 1998 (+0.53°C/0.95°F) 2007 (+0.65°C/1.17°F) |
Northern HemisphereLandOcean Land and Ocean |
+0.89°C (+1.60°F) +0.31°C (+0.56°F) +0.53°C (+0.95°F) |
10th warmest 8th warmest 8th warmest |
2007 (+1.48°C/2.66°F) 1998 (+0.50°C/0.90°F) 2007 (+0.83°C/1.49°F) |
Southern HemisphereLandOcean Land and Ocean |
+0.32°C (+0.58°F) +0.31°C (+0.56°F) +0.31°C (+0.56°F) |
18th warmest 22nd warmest 20th warmest |
2005 (+0.89°C/1.60°F) 1998 (+0.57°C/1.03°F) 1998 (+0.61°C/1.10°F) |
The most current data may be accessed via the Global Surface Temperature Anomalies page.
The maps below represent anomaly values based on the GHCN data set of land surface stations using a base period of 1961-1990. During boreal spring, above-average precipitation fell over areas that included the Philippines, parts of Europe, Asia, and South America, and most of the eastern half of the contiguous U.S. Drier-than-average conditions were observed in the Hawaiian Islands, southeastern China, southern Africa, the northwestern and parts of the southern continental U.S., most of Australia, and parts of Paraguay and Argentina.
During May 2008, above-average precipitation fell over areas that included the Philippines, southern Burma, Japan, northeastern China, southwestern Europe, parts of South America, and from the northern Plains to the Lower Mississippi Valley. Drier-than-average conditions were observed across the Hawaiian Islands, British Isles, Sri Lanka, central Europe, parts of India, eastern China, northern Argentina, Paraguay, and most of Australia.
According to Australia's Bureau of Meteorology (BoM), precipitation across Australia was 73 percent below normal during May, resulting in the driest May on record. May 2008 had a national average of 7.86 mm (0.31 inches) of rain, surpassing the previous record of 8.27 mm (0.32 inches) set in 1961. During March-May, Australia, as a whole, experienced 53 percent below-normal precipitation, resulting in the eighth driest austral autumn.
During May 2008, typhoon Rammasun and typhoon Halong brought heavy rain across the Philippines, prompting widespread floods and landslides on the islands. Tropical cyclone Nargis, the most devastating cyclone to strike Asia since 1991, caused widespread floods across Burma (Myanmar). This resulted in the worst natural disaster ever recorded in the country. Heavy rain during May 21-26 prompted flash floods and landslides that killed 5 people and displaced nearly 15,000 people across south-central Chile. Additional details on flooding and drought can also be found on the May Global Hazards page.
Sea surface temperature (SST) anomalies in the Niño 3.4 and 4 regions warmed, but remained below average during May. Niño 1+2 region SST anomalies remained above average. These conditions are indicative of a weakening ENSO cold event (as shown in the adjacent animation of weekly SST anomalies). A comprehensive summary of May 2008 ENSO conditions can be found on the ENSO monitoring page. For the latest advisory on ENSO conditions go to NOAA's Climate Prediction center (CPC) and the CPC ENSO Diagnostic Discussion.
Images of sea surface temperature conditions are available for all weeks since 2003 at the weekly SST page.
As shown in the time series to the right, the mean Northern Hemisphere snow cover extent during spring 2008 was below average, resulting in the 3rd least snow cover extent on record, behind 1968 and 1990. Much of this was due to the anomalously warm conditions across Asia, Europe, and parts of Alaska and Canada during the boreal spring. The mean Northern Hemisphere spring snow cover extent for the 1967-2008 period of record is 30.8 million square kilometers.
Across North America, snow cover during spring 2008 was slightly above average, due to a series of snow storms that struck the U.S. early in the season. This resulted in the 14th largest extent since satellite records began in 1967. The mean North American spring snow cover extent is 12.9 million square kilometers for the 1967-2008 period of record.
As depicted in the time series to the right, Eurasian snow cover extent during spring 2008 was the least since satellite records began in 1967. This can be primarily attributed to warm spring temperatures across the Eurasian continent during the spring, which triggered rapid snow melt. On average, the Eurasian boreal spring snow cover extent is 17.9 million square kilometers for the 1967-2008 period of record.
Data were provided by the Global Snow Laboratory, Rutgers University.
According to the National Snow and Ice Data Center, the May 2008 Northern Hemisphere sea ice extent, which is measured from passive microwave instruments onboard NOAA satellites, was below the 1979-2000 mean, but greater than the previous six years. This was the tenth least May sea ice extent on record. Sea ice extent for May has decreased at a rate of 2.7 percent per decade since satellite records began in 1979, as temperatures in the high latitude Northern Hemisphere have risen at a rate of approximately 0.37°C per decade over the same period.
Meanwhile, the May 2008 Southern Hemisphere sea ice extent exceeded the 1979-2000 mean. This was the third greatest sea ice extent in May (7.4 percent above the 1979-2000 mean) over the 30-year historical period, behind 2000 and 1996. Sea ice extent for May has increased at a rate of 1.8 percent per decade.
For further information on the Northern and Southern Hemisphere snow and ice conditions, please visit the NSIDC News page, provided by the NOAA's National Snow and Ice Data center (NSIDC).
Temperatures above the Earth's surface are measured within the lower Troposphere, middle Troposphere, and Stratosphere using in-situ balloon-borne instruments (radiosondes) and polar-orbiting satellites (NOAA's TIROS-N). The radiosonde and satellite records have been adjusted to remove time-dependent biases (inhomogeneities caused by changes in radiosonde instruments and measurement practices as well as changes in satellite instruments and orbital features through time).
Current Month / Seasonal / Year-to-date
These temperatures are for the lowest 8 km (5 miles) of the atmosphere. Information on the UAH and RSS sources of troposphere data is available.
| May | Anomaly | Rank | Warmest (or Next Warmest) Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | -0.17°C/-0.31°F | 26th warmest (5th coolest) |
1998 (+0.65°C/1.17°F) | +0.07°C/decade |
| *RSS low-trop | -0.08°C/-0.14°F | 23rd warmest (8th coolest) |
1998 (+0.70°C/1.26°F) | +0.14°C/decade |
*Version 03_0
| March- May |
Anomaly | Rank | Warmest (or Next Warmest) Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | -0.02°C/-0.04°F | 19th warmest | 1998 (+0.65°C/1.17°F) | +0.11°C/decade |
| *RSS low-trop | +0.03°C/0.05°F | 18th warmest | 1998 (+0.73°C/1.31°F) | +0.16°C/decade |
*Version 03_0
| January- May |
Anomaly | Rank | Warmest (or Next Warmest) Year on Record | Trend |
|---|---|---|---|---|
| UAH low-trop | -0.02°C/-0.04°F | 20th warmest (11th coolest) |
1998 (+0.66°C/1.19°F) | +0.14°C/decade |
| *RSS low-trop | 0.00°C/0.00°F | 20th warmest | 1998 (+0.71°C/1.28°F) | +0.17°C/decade |
*Version 03_0
Current Month / Seasonal / Year-to-date
These temperatures are for the atmospheric layer centered in the mid-troposphere (approximately 3-10 km (2-6 miles) above the Earth's surface), which also includes a portion of the lower Stratosphere. (The MSU channel used to measure mid-tropospheric temperatures receives about 25 percent of its signal above 10 km (6 miles).) Because the Stratosphere has cooled due to increasing greenhouse gases in the Troposphere and losses of ozone in the Stratosphere, the stratospheric contribution to the tropospheric average, as measured from satellites, may create an artificial component of cooling to the mid-Troposphere temperatures. The University of Washington (UW) versions of the UAH and RSS analyses attempt to remove the stratospheric influence from the mid-troposphere measurements, and as a result the UW versions tend to have a larger warming trend than either the University of Alabama-Huntsville (UAH) or Remoste Sensing Systems (RSS) versions. For additional information, please see NCDC's Microwave Sounding Unit page.
The radiosonde data used in this global analysis were developed using the Lanzante, Klein, Seidel (2003) ("LKS") bias-adjusted dataset and the First Difference Method (Free et al. 2004) (RATPAC). Additional details are available. Satellite data have been adjusted by the Global Hydrology and Climate Center at the UAH. An independent analysis is also performed by RSS and a third analysis has been performed by Dr. Qiang Fu of the UW (Fu et al. 2004)** to remove the influence of the stratosphere on the mid-troposphere value. Global averages from radiosonde data are available from 1958 to present, while satellite measurements began in 1979.
Radiosonde measurements indicate that for the January-May year-to-date period, temperatures in the mid-Troposphere were 0.14°C (0.25°F) above average, resulting in the twentieth warmest January-May since global measurements began in 1958. However, as shown in the table below, satellite measurement of the January-May year-to-date period for the middle Troposphere were cooler than average, varying from fourth coolest (twenty-seventh warmest) to tenth coolest (twenty-first warmest) on record.
Similar to January-May year-to-date, radiosonde measurements indicate that temperatures were 0.14°C (0.25°F) above average during the boreal spring, giving March-May a rank of twenty-third warmest on record. The table below shows that satellite measurements for the boreal spring were also cooler than normal, ranking from third coolest (twenty-eighth warmest) to eleventh coolest (twentieth warmest) on record.
The global mid-Troposphere temperatures were cooler than average during May 2008. As shown in the table below, satellite measurement for May 2008 ranked from second coolest (twenty-ninth warmest) to ninth coolest (twenty-second warmest) record.
| May | Anomaly | Rank | Warmest (or Next Warmest) Year on Record | Trend |
|---|---|---|---|---|
| UAH mid-trop | -0.29°C/-0.52°F | 29th warmest (2nd coolest) |
1998 (+0.61°C/1.10°F) | +0.01°C/decade |
| *RSS mid-trop | -0.19°C/-0.34°F | 28th warmest (3rd coolest) |
1998 (+0.65°C/1.17°F) | +0.08°C/decade |
| **UW-UAH mid-trop | -0.19°C/-0.34°F | 28th warmest (3rd coolest) |
1998 (+0.77°C/1.39°F) | +0.07°C/decade |
| **UW-*RSS mid-trop | -0.13°C/-0.23°F | 22nd warmest (9th coolest) |
1998 (+0.77°C/1.39°F) | +0.13°C/decade |
*Version 03_0
| March- May |
Anomaly | Rank | Warmest (or Next Warmest) Year on Record | Trend |
|---|---|---|---|---|
| UAH mid-trop | -0.21°C/-0.38°F | 28th warmest (3rd coolest) |
1998 (+0.61°C/1.10°F) | +0.03°C/decade |
| *RSS mid-trop | -0.12°C/-0.22°F | 23rd warmest (8th coolest) |
1998 (+0.65°C/1.17°F) | +0.09°C/decade |
| **UW-UAH mid-trop | -0.12°C/-0.22°F | 24th warmest (7th coolest) |
1998 (+0.74°C/1.33°F) | +0.10°C/decade |
| **UW-*RSS mid-trop | -0.04°C/-0.07°F | 20th warmest (11th coolest) |
1998 (+0.77°C/1.39°F) | +0.15°C/decade |
| RATPAC | +0.14°C/0.25°F | 23rd warmest | 1998 (+0.86°C/1.55°F) | +0.14°C/decade |
*Version 03_0
| January- May |
Anomaly | Rank | Warmest (or Next Warmest) Year on Record | Trend |
|---|---|---|---|---|
| UAH mid-trop | -0.17°C/-0.31°F | 27th warmest (4th coolest) |
1998 (+0.60°C/1.08°F) | +0.04°C/decade |
| *RSS mid-trop | -0.10°C/-0.18°F | 24th warmest (7th coolest) |
1998 (+0.64°C/1.15°F) | +0.10°C/decade |
| **UW-UAH mid-trop | -0.08°C/-0.14°F | 22nd warmest (9th coolest) |
1998 (+0.73°C/1.31°F) | +0.11°C/decade |
| **UW-*RSS mid-trop | -0.02°C/-0.04°F | 21st warmest (10th coolest) |
1998 (+0.76°C/1.37°F) | +0.16°C/decade |
| RATPAC | +0.14°C/0.25°F | 20th warmest | 1998 (+0.80°C/1.44°F) | +0.14°C/decade |
*Version 03_0
The table below summarizes stratospheric conditions for May and Mar-May 2008. On average, the Stratosphere is located approximately between 16-23 km (10-14 miles) above the Earth's surface. Over the last decade, stratospheric temperatures have been below average in part due to the depletion of ozone. The large positive anomaly in 1982 was caused by the volcanic eruption of El Chichon in Mexico, and the sharp jump in temperature in 1991 was a result of the eruption of Mt. Pinatubo in the Philippines. In both cases the temperatures returned to pre-eruption levels within two years.
| May | Anomaly | Rank | Coolest (or Next Coolest) Year on Record |
|---|---|---|---|
| UAH stratosphere | -0.63°C (-1.13°F) | coolest | 1996 (-0.62°C/-1.12°F) |
| *RSS stratosphere | -0.48°C (-0.86°F) | 3rd coolest | 1996 (-0.53°C/-0.95°F) |
*Version 03_0
| March- May |
Anomaly | Rank | Coolest (or Next Coolest) Year on Record |
|---|---|---|---|
| UAH stratosphere | -0.61°C (-1.10°F) | 2nd coolest | 1999 (-0.63°C/-1.13°F) |
| *RSS stratosphere | -0.52°C (-0.94°F) | 2nd coolest | 1999 (-0.56°C/-1.01°F) |
*Version 03_0
For additional details on precipitation and temperatures in May, see the Global Hazards page.
Christy, John R., R.W. Spencer, and W.D. Braswell, 2000: MSU Tropospheric Temperatures: Dataset Construction and Radiosonde Comparisons. J. of Atmos. and Oceanic Technology, 17, 1153-1170.
Free, M., D.J. Seidel, J.K. Angell, J. Lanzante, I. Durre and T.C. Peterson (2005) Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC): A new dataset of large-area anomaly time series, J. Geophys. Res., 10.1029/2005JD006169.
Free, M., J.K. Angell, I. Durre, J. Lanzante, T.C. Peterson and D.J. Seidel(2004), Using first differences to reduce inhomogeneity in radiosonde temperature datasets, J. Climate, 21, 4171-4179.
Fu, Q., C.M. Johanson, S.G. Warren, and D.J. Seidel, 2004: Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends. Nature, 429, 55-58.
Lanzante, J.R., S.A. Klein, and D.J. Seidel (2003a), Temporal homogenization of monthly radiosonde temperature data. Part I: Methodology, J. Climate, 16, 224-240.
Lanzante, J.R., S.A. Klein, and D.J. Seidel (2003b), Temporal homogenization of monthly radiosonde temperature data. Part II: trends, sensitivities, and MSU comparison, J. Climate, 16, 241 262.
Mears, Carl A., M.C. Schabel, F.J. Wentz, 2003: A Reanalysis of the MSU Channel 2 tropospheric Temperature Record. J. Clim, 16, 3650-3664.
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.
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