Washington ? Last month was the second warmest April on record worldwide, and was warmer and drier than usual for much of the United States.

The conditions led to a worsening drought in parts of the United States, particularly the Southwest and many cities along the Eastern seaboard, the National Climatic Data Center reported Thursday.

Overall it was the ninth warmest April on record for the United States at an average of 54.6 degrees Fahrenheit in the 48 contiguous states. That is 2.6 degrees above the 1895-2002 long-term average.

Worldwide, preliminary data show the average land and ocean temperature in April was 56.7 degrees Fahrenheit, 1.03 degrees above the long-term average. That’s the second warmest average since 1880. The warmest April worldwide was in 1998, when a strong El Nino warming of the equatorial Pacific Ocean helped raise the readings. Researchers report that another El Nino is developing, with sea-surface temperatures rising above their usual levels in the Pacific.

The center reported that severe drought affected about 21 percent of the contiguous United States as of the end of April. That was down from 36 percent last August.

There are long-term water deficits in much of the West, especially in the Rockies.