Driven by exceptionally warm ocean waters, Earth surpassed a record for heat in May and likely will continue to break high-temperature marks, experts say. The U.S. National Oceanic and Atmospheric Administration (NOAA) reported Monday that the May average temperature of 15.54 degrees Celsius beat the previous record set four years ago. In April, the world matched the 2010 record for that month. Records date from 1880. May was especially warm in parts of Kazakhstan, Indonesia, Spain, South Korea, and Australia, while the United States had a relatively cool year, not much warmer than the 20th century average. May was 0.74 degree warmer than the 20th century world average. The last time a month was cooler than normal was February 1985, so there have been 351 consecutive warmer-than-average months. Climate scientists say there is a good chance global heat records will continue to be broken, especially next year because an El Nino weather event is adding to man-made global warming. An El Nino is a warming of the eastern tropical Pacific Ocean that alters climate worldwide and usually increases global temperatures. Ocean temperatures in May also set a record for the month, but an El Nino is not considered in effect until the warm water changes the air, and that has not happened yet, NOAA says.