May 2014 Global Climate Report

Note: official monthly data for China were not received in time for inclusion in this analysis. For the purposes of this report, NCDC calculated data for China using daily reports from its GHCN-Daily dataset. When official monthly data are received from China, they will replace the NCDC calculations. The contents of this report will not be altered, but the long-term record at NCDC's Global Temperature Anomalies Page will reflect the official data.

May 2014 Selected Climate
Anomalies and Events Map

Global Highlights

• The combined average temperature over global land and ocean surfaces for May 2014 was record highest for this month, at 0.74°C (1.33°F) above the 20^th century average of 14.8°C (58.6°F).
  
• The global land surface temperature was 1.13°C (2.03°F) above the 20^th century average of 11.1°C (52.0°F), the fourth highest for May on record. For the ocean, the May global sea surface temperature was 0.59°C (1.06°F) above the 20^th century average of 16.3°C (61.3°F), making it the record highest for May and tying with June 1998, October 2003, and July 2009 as the highest departure from average for any month on record.
  
• The combined global land and ocean average surface temperature for the March–May period was 0.74°C (1.33°F) above the 20^th century average of 13.7°C (56.7°F), making it the second warmest such period on record, behind 2010.
  
• The March–May worldwide land surface temperature was 1.26°C (2.27°F) above the 20^th century average, the third warmest such period on record. The global ocean surface temperature for the same period was 0.54°C (0.97°F) above the 20^th century average, also the third warmest March–May on record.
  
• The combined global land and ocean average surface temperature for the January–May period (year-to-date) was 0.66°C (1.19°F) above the 20^th century average of 13.1°C (55.5°F), the fifth warmest such period on record.
  

Introduction

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 maps on the right are percentile maps that complement the information provided by the anomaly maps. These 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.

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

Temperatures

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 May 2014 and March 2014–May 2014 maps—is generally reflected by areas of positive and negative temperature anomalies at the surface, respectively.

May

May 2014 Blended Land and Sea Surface
Temperature Anomalies in degrees Celsius

May 2014 Blended Land and Sea Surface
Temperature Percentiles

With records dating back to 1880, the combined average temperature over global land and ocean surfaces reached a record high for May, at 0.74°C (1.33°F) higher than the 20^th century average. This surpassed the previous record high anomaly of 0.72°C (1.30°F) set in 2010. Four of the five warmest Mays on record have occurred in the past five years: 2010 (second warmest), 2012 (third warmest), 2013 (fifth warmest), and 2014 (warmest); currently, 1998 has the fourth warmest May on record. Additionally, May 2014 marked the 39^th consecutive May and 351^st consecutive month (more than 29 years) with a global temperature above the 20^th century average. The last below-average global temperature for May occurred in 1976 and the last below-average temperature for any month occurred in February 1985.

The average land surface temperature for the globe was the fourth highest for May in the 135-year period of record, at 1.13°C (2.03°F) higher than average. The seven warmest Mays over land have all been observed during the 21^st century, with the four warmest occurring since 2010. At the hemispheric scale, while the Northern Hemisphere land areas were sixth warmest for that particular region of the globe, the Southern Hemisphere land was record warm for May, surpassing the previous highest May temperature (set in 2002) by 0.17°C (0.31°F).

Select national information is highlighted below. (Please note that different countries report anomalies with respect to different base periods. The information provided here is based directly upon these data):

• Warmer-than-average temperatures continued in Australia during May, with the nationally-averaged mean temperature third highest on record for the month, at 1.62°C (2.92°F) above the 1961–90 average. South Australia had a record high average May temperature, at 2.67°C (4.81 deg;F) above average, beating the previous record of +2.57°C (+4.63°F) set just one year ago. Only the state of Tasmania had an average May temperature that did not rank among its 10 warmest; however, it was still 0.90°C (1.62°F) higher than average. Additionally, every state had both above-average monthly minimum and maximum temperatures.
• In Austria, May was the first month since May 2013 with a national temperature below the 1981–2010 monthly average, at 0.6°C (1.1°F) below normal.
• Spain observed a May temperature that was 1.4°C (2.5°F) higher than the 1971–2000 average. Most of the southern half of the country was 2°–3°C. (4°–5°F) warmer than average.
• With records dating back to 1973, South Korea reported its highest average May temperature on record, at 1.2°C (2.2°F) above the 1981–2010 average. The average maximum temperature for the country was second highest in the period of record, at 1.7°C (3.1°F) above average.
• In North America, the U.S. state of Alaska had its sixth warmest May since records began in 1918, at 3.56°F (1.98°C) above the 1971–2000 average.

Across the oceans, the global monthly-averaged sea surface temperature was 0.59°C (1.06°F) higher than the 20^th century average, marking the highest May temperature on record. The previous high temperature record for May was set in 1998. It also ties with June 1998, October 2003, and July 2009 as the highest departure from average for any month on record. This record high temperature was observed as conditions, although still officially ENSO-neutral, continued to evolve toward El Niño in the east central equatorial Pacific Ocean. According to NOAA's Climate Prediction Center, there is about a 70 percent chance that El Niño conditions will develop during the Northern Hemisphere summer 2014 and an 80 percent chance it will develop during the fall or winter. This forecast focuses on the ocean surface temperatures between 5°N and 5°S latitude and 170°W to 120°W longitude.

May Global Land and Ocean plot

May Global Hemisphere plot

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

Seasonal (March–May)

March 2014–May 2014 Blended Land and Sea Surface
Temperature Anomalies in degrees Celsius

March 2014–May 2014 Blended Land and Sea Surface
Temperature Percentiles

March–May 2014 was the second warmest such period across global land and ocean surfaces, behind only 2010, since record keeping began in 1880, at 0.74°C (1.33°F) higher than the 20^th century average. The land and ocean temperatures were equal contributors to the global average, as each separately had their third highest average March–May temperature on record. Additionally, the warmth was spread rather evenly across the hemispheres, with the Northern Hemisphere having its second highest average spring temperature on record, behind 2010, and the Southern Hemisphere observing its fourth highest fall temperature.

Select national information is highlighted below. (Please note that different countries report anomalies with respect to different base periods. The information provided here is based directly upon these data):

• Austral fall was the third warmest for Australia since national records began in 1910, with a mean temperature 1.15°C (2.07°F) above the 1961–90 average. With the exception of the Northern Territory, every state observed average fall temperatures among their 10 highest on record. South Australia had its highest average fall minimum temperature on record, at 1.86°C (3.29°F) above average, breaking the previous record of +1.83°C (3.29°F) set in 2013.
• Even with a cooler-than-average May, Austria reported its seventh warmest spring (March–May) in its 247-year period of record, at 1.5°C (2.7°F) higher than the 1981–2010 average.
• It was the third warmest spring for the United Kingdom since records began in 1910, behind 2007 and 2011, at 1.3°C (2.3°F) above the 1981–2010 average. Scotland had its warmest spring on record. The average minimum temperature across the UK was the highest for March–May on record.
• In Denmark, spring 2014 tied with 1990 as the second warmest spring (behind 2007) since national records began in 1872. It was 2.5°C (4.5°F) higher than the 1961–1990 average and 1.4°C (2.5°F) higher than the most recent 2001–2010 decadal average.
• Norway observed its warmest spring since national records began in 1900, at 2.3°C (4.1°F) above the 1981–2010 average, surpassing the previous warmest spring of 2002.
• With records dating back to 1922, Latvia also reported its warmest spring on record, at 2.7°C (4.9°F) higher than average and breaking the previous record (set in 2002 and tied in 2007) by 0.2°C (0.4°F). This was due largely to the country observing its third warmest March and fifth warmest April on record during this period. Spring temperatures in Latvia are increasing at the fastest rate among all seasons, with the average temperature rising by 2.6°C over the past century, according to Latvijas Vides Geologijas un Meteorologijas Centrs.
• Due in part to the record warmth during May, South Korea observed its second highest average spring temperature on record, behind only 1998. The average maximum temperature was record high for the month, while the average minimum temperature was second highest.

March–May Global Land and Ocean plot

March–May Global Hemisphere plot

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

Year-to-date (January–May)

January–May 2014 Blended Land and Sea Surface
Temperature Anomalies in degrees Celsius

January–May 2014 Blended Land and Sea Surface
Temperature Percentiles

The first five months of 2014 was Earth's fifth warmest such period, with a combined average land and ocean surface temperature that was 0.66°C (1.19°F) above the 20^th century average. With the exception of February (21^st warmest), each monthly temperature in 2014 to date has ranked among the four highest for its respective month.

The globally-averaged sea surface temperature was the third highest for this five-month period, behind 1998 and 2010, which tied for record highest. The globally-averaged land temperature was the fifth highest since records began in 1880. Record warmth was observed in many areas across the world, including parts of the western North and South Atlantic Ocean, sections of the northeastern and equatorial Pacific, areas of the Norwegian and Barents Seas, the ocean waters south of Africa, far western Alaska and parts of Far East Russia, part of the western United States, southern Mexico, and central to eastern Australia. A section of central North America near the Great Lakes region and Southern Ocean waters between South America and Antarctica were record cold for January–May.

January–May Global Land and Ocean plot

January–May Global Hemisphere plot

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

Precipitation

May

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 May 2014 varied significantly around the world. As indicated by the May precipitation percentiles map below, extreme wetness was observed during May over parts of central and eastern Europe, along with small sections in both eastern and western equatorial Africa. Extreme dryness was scattered across different parts of the globe, including northern and eastern South America, and parts of northern and eastern Australia.

Select national information is highlighted below. (Please note that different countries report anomalies with respect to different base periods. The information provided here is based directly upon these data):

• Some regions in northern and eastern Austria received record monthly rainfall for May. The region north of Salzburg to Mattersburg observed 230 percent of average May precipitation, the most since records began in 1820. Several individual stations set new May records.
• Across Spain, May rainfall was just 50 percent of average, at 33 mm (1.3 inches), with parts of central and southern Spain recording less than 25 percent of their average precipitation.

May 2014 Land-Only Precipitation
Percent of Normal

May 2014 Land-Only Precipitation Percentiles

Seasonal (March–May)

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 March 2014–May 2014 varied significantly around the world.

• Spring was among the 10 wettest on record for Norway in its 115-year period of record. Some stations in northern Norway reported more than 200 percent of average precipitation for the season.

March 2014 – May 2014 Land-Only Precipitation
Percent of Normal

March 2014 – May 2014 Land-Only Precipitation Percentiles

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.

Citing This Report

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