Climate bulletin - May 2014

Summary of the world's climate in May 2014.

The global average temperature for May 2014 as estimated from the  HadCRUT4 data set was 0.59 ± 0.17 °C above the 1961-1990 average. Although the central estimate of 0.59 °C for May 2014 suggests that it was the warmest May on record, the difficulties of measuring global average temperature are such that it is not possible to provide a definitive ranking. Other very warm Mays such as 2010 (0.58 ± 0.16 °C), 1998 (0.57 ± 0.15 °C) and 2012 (0.54 ± 0.18 °C) were comparable within the estimated margin of error. Other global temperature data sets maintained by  NASA GISS and NOAA NCDC also show that May was an exceptionally warm month globally.

Sea-surface temperatures (SSTs) in the Tropical Pacific were above the long-term average, but conditions are not yet indicative of an El Niño event. Below the surface, water temperatures in the Tropical Pacific were above average from the dateline to the coast of South America.

During May, the global average air temperature over land was warmer than the long-term average (0.92 ± 0.29 °C). Parts of Alaska and the west coast of north America, along with South Africa, large areas of Australia and eastern Asia were significantly warmer than the long term mean. In addition an area across north Africa, extending through the Middle East in to central Asia was also unusually warm. Areas of significant cold were less widespread with an area just west of Lake Baikal experiencing unusual cold for the time of year and some isolated island stations in the southern hemisphere.

SSTs were generally warmer than average in May (0.48 ± 0.08 °C). Large areas of unusual warmth were recorded in the north-east Pacific, parts of the North Atlantic, Indian Ocean, South Atlantic and western tropical Pacific. Areas of unusually cold waters were more limited. An area of the North Atlantic around 45 °N was unusually cold. Other areas of unusually cold sea-surface temperatures were the western Pacific around 30 °N, the Gulf of Mexico and an area of the eastern Pacific around 15-30 °S.

In the southern hemisphere, the sea ice surrounding Antarctica reached a record extent for May. The ice was particularly extensive (relative to the long term mean) in the Weddell Sea sector.

Last updated: 7 July 2014