Washington, October 14 - NOAA reported today that September 1998 was the warmest September on record both globally and in the contiguous United States.

Global Data for September and the Year-to-Date

At 59.98 degrees Fahrenheit, September 1998 was 1.08 degree F above the 1880-1997 mean global temperature of 58.9 degrees F. This continues the unprecedented string of record-breaking monthly global temperatures, which began just last year during the very strong El Niño event.

Despite the cooling in the equatorial Pacific associated with La Niña, the average global ocean temperature for September 1998 was tied for the second warmest. The remarkably warm land temperatures (0.56 degrees F warmer than last September, the previous record) drove the global average to a new record high.

The period January through September also established an all-time record high. Temperatures averaged 57.4 degrees F, or more than 1.25 degrees F above the 1880-1997 long-term mean for the period. The high temperatures were particularly evident over the land as temperatures averaged nearly two degrees above the long-term mean.

"The recent string of unusually high global average temperatures could be a sign of accelerated global warming," explained Thomas Karl, director of NOAA's National Climatic Data Center in Asheville, N.C. "However, these records will not continue indefinitely because of the impacts of normal climate variability."

"In particular, as the developing La Niña matures, it will be an even more important factor affecting global temperatures, just as El Niño acted to enhance global temperatures," added Karl. "The continued long-term increase in global temperatures is consistent with the International Panel on Climate Change's statement on the human influence on climate."

Global Data for the Summer

Globally, the summer of 1998 had an average temperature of 62.06 degrees F. This is 1.2 degrees F above the 1880-1997 mean. The warmest all-time temperature for one month for the planet occurred in July, with a temperature of 61.62 degrees F, or 1.22 degrees above the average.

U.S. Data for September

Not only did the global temperatures exceed all previous September monthly means, but so did the average temperatures in the contiguous United States, beating the record heat during the Dust Bowl years of the 1930s.

Preliminary data from NOAA's Asheville center and the National Centers for Environmental Prediction in Camp Springs, Md., show that September 1998, with a national averaged temperature of 69.1 degrees Fahrenheit, surpassed the previous record of 68.4 degrees F, set in September 1931. The 1961-1990 normal temperature for the United States during September is 64.8 degrees F. September 1998 surpassed this by 4.3 degrees.

Three states – Montana, Oklahoma, and Wyoming – had the warmest September in 1998. Montana had an average temperature of 61.9 degrees F, or 7.4 degrees above normal. Oklahoma had an average temperature of 80.2 degrees F, or 7.9 degrees above normal. Wyoming had an average of 60.1 degrees F, or 5.8 degrees above normal.

September continued the string of extreme weather and climate that the United States experienced all spring and summer. Eugene, Ore., went 83 days without rain, from June 27 till September 17, setting a new record. Several records were set for high temperatures for September: Oklahoma City was 107 degrees F on Sept. 3; Dallas-Ft. Worth was 108 degrees F on Sept. 4; Scottsbluff, Neb., was 102 degrees F on Sept. 5.

Summer in the United States

Nationally, at 72.9 degrees Fahrenheit, summer (June through August) was the ninth warmest on record since detailed records began in 1895, according to preliminary data.
The 1961-1990 normal summer temperature is 71.7 degrees F. The 1998 average summer temperature was 72.9 degrees. The warmest summer on record, with a national average temperature of 74.3 degrees, was in 1936. The coolest summer on record was in 1915, at 69.5 degrees F.

Summer 1998 was also the 44th driest. The 1961-1990 normal summer precipitation for the United States is 8.24 inches. The 1998 summer precipitation was 8.19 inches. The wettest summer on record was in 1928 with a national average precipitation of 10.24 inches. The driest summer on record, with only 5.98 inches of precipitation, was in 1930.

U.S. Regional Temperatures and Precipitation for the Summer

Regionally, summer 1998 was the fourth warmest for the South and the sixth warmest for the Southeast. Summer 1998 was the warmest on record for Florida and Louisiana, third warmest for Texas, fourth warmest for Washington, and fifth warmest for Oklahoma.

Based on preliminary data, summer 1998 was the fifth driest on record for Maryland, the eighth driest for Delaware, Georgia, and South Carolina; ninth driest for Florida, and the 10th driest for New Jersey.

To the opposite extreme, summer 1998 was the second wettest on record for Wyoming, third wettest for Vermont, and seventh wettest for Colorado, Iowa, and Missouri.

Year-to-Date Climate in the United States

Preliminary data indicate that the period January-September 1998 was the second warmest such year-to-date period for the United States, with a national averaged temperature of 57.64 degrees Fahrenheit. The warmest January-September was 57.72 degrees F, which occurred in 1934; the coolest was 53.30 degrees F in 1912.

The 1961-1990 normal January-September temperature for the United States is 55.40 degrees. Eight states – Connecticut, Delaware, Maryland, New Hampshire, New Jersey, Rhode Island, Vermont, and Wisconsin – had the warmest January-September in 1998.

Notes to Editors: More information is available at:
http://nic.fb4.noaa.gov Click on Climate Monitoring; click on U.S.A.; click on United States. Click on Monthly.

See also: http://www.ncdc.noaa.gov/ol/climate/research/1998/sep/sep98.html

For more information contact Patricia Viets at (301) 457-5005 or Stephanie Kenitzer at (301) 763-8000 ext. 7007.