Spring 2010 (March 1–May 31)

• The seasonal (March–May 2010) worldwide ocean surface temperature was the second warmest such period on record, 0.55°C (0.99°F) above the 20^th century average of 16.1°C (61.0°F).
• The global land surface temperatures for May and the March–May period were the warmest on record, at 1.04°C (1.87°F) and 1.22°C (2.20°F) above the 20^th century average, respectively.
• In the Northern Hemisphere, both the May 2010 average temperature for land areas, and the hemisphere as a whole (land and ocean surface combined), represented the warmest May on record. The Northern Hemisphere ocean temperature was the second warmest May on record. The average combined land and ocean surface temperature for the Northern Hemisphere was also record warmest for the March–May period.
• El Niño ended during May 2010. Sea surface temperature anomalies in the eastern equatorial Pacific Ocean cooled below the El Niño threshold, signifying a return to ENSO-neutral conditions. According to NOAA's Climate Prediction Center, sea surface cooling could result in a La Niña during the Northern Hemisphere summer 2010.