Summer 2012 was the USA's third-hottest on record

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The USA just endured its third-hottest summer on record, and it looks like the fall is on track to be warmer than average too, scientists reported Monday.

For the entire year to date, the nation is having its warmest year since records began in 1895, said the report by the National Climatic Data Center in Asheville, N.C.

About 80 million Americans sweltered through 100-degree temperatures at some point this summer, the climate center noted in its report.

The warmth should continue for much of the nation over the next several months: "We're looking at a warmer-than-average fall," especially east of the Rockies, AccuWeather meteorologist Jack Boston said. He adds that cooler-than-average temperatures should be confined to the far west this fall, however, with mountain snows possible by early October.

With the El Niño climate pattern now in effect, "the best chances for above-normal temperatures this fall are in the northern tier of the nation," mainly east of the Rockies, forecaster Jon Gottschalck of the Climate Prediction Center said.

El Niño is a periodic warming of Pacific Ocean water temperatures that influences weather in the USA and around the world.

The summer heat this year really ramped up in July, which ended up as the hottest month in U.S. history. "The heat was widespread in July," scientist Jake Crouch of the National Climatic Data Center said. The worst of the heat eased a bit in August, he said, which prevented the summer from being the hottest on record.

The climate center defines summer as June 1-Aug. 31. Seven of the 10 hottest summers in U.S. history have occurred since 2000, and the nation has experienced its second- and third-warmest summers in back-to-back years.

This may be a signal of climate change: "All of this fits into the longer-term warming trend," Crouch told the environmental group Climate Central.

Other highlights of summer:

• The average U.S. temperature during the summer was 74.4 degrees, which was 2.3 degrees above the long-term (1901-2000) average. Only 1936, at 74.6 degrees, and 2011, at 74.5 degrees, were warmer.

• Two states — Colorado and Wyoming — had their warmest summer on record.

• As for rainfall, the nation saw extremes this summer: Nebraska and Wyoming had their driest summer on record, while Florida had its wettest summer.