BOSTON (Bloomberg) — This year has a 90 percent chance of ending as the warmest on record in the lower 48 states, the U.S. National Climatic Data Center said Thursday.

Temperatures from January through October were 1.1 degrees Fahrenheit (0.6 Celsius) higher than the previous mark, set in 1998, and 3.4 degrees above the long-term average, said Jake Crouch, a climatologist at the center in Asheville, N.C. U.S. records go back to 1895.

Warmer-than-normal weather earlier this year reduced the need for energy to heat homes and businesses, and hurt gas futures in April. November and December will have to be “much cooler than average” to keep 2012 from becoming the warmest year ever in the contiguous 48 states, the climate center said.

Globally, temperatures are currently 1.04 degrees above average, on pace for the eighth warmest year on record, according to the center.

At the same time, the extent of snowcover across the Northern Hemisphere in October was the eighth-largest on record, Crouch said in a conference call with reporters. Arctic sea ice was at its second-smallest level in October.

Scientists are still studying the impact sea ice and snowcover have on weather patterns across the Northern Hemisphere, said Jon Gottschalck, a seasonal forecaster at the U.S. Climate Prediction Center in College Park, Md. There is some research that shows less sea ice at the pole and more snowcover across the hemisphere can lead to cooler weather in the eastern U.S.

Because that connection is still being researched, forecasters didn’t use it when making their prediction for the next three months, Gottschalck said.

The forecast is for an above-average chance that temperatures will be higher than normal from the Rocky Mountains into Texas and potentially lower than normal across the northern Great Plains. He couldn’t predict with any certainty what would happen in the eastern U.S.

Another problem with making a long-range forecast this year is that an El Nino, a warming in the Pacific Ocean, failed to take place as expected, Gottschalck said. El Ninos usually bring warmer-than-normal weather across the northern U.S.