Des Moines, Iowa ? Warmer and wetter weather in large swaths of the country have helped farmers grow corn, soybeans and other crops in some regions that only a few decades ago were too dry or cold, experts who are studying the change said.

Bruce Babcock, an Iowa State University agriculture economist, said soybean production is expanding north and the cornbelt is expanding north and west because of earlier planting dates and later freezes in the fall.

“The Dakotas are pretty big corn producers now and soybeans have dramatically increased in North and South Dakota,” Babcock said.

The change is due in part to a 7 percent increase in average U.S. rainfall in the past 50 years, said Jay Lawrimore, chief of climatic analysis for the Asheville, N.C.-based National Climactic Data Center.

“The storm tracks are moving northward as the climate warms,” Lawrimore said.

The Earth’s temperature has risen about 1.3 degrees since the late 1800s, according to data from the NCDC, with the warming greatest over North America, Europe and Asia. Seven of the eight warmest years on record have occurred since 2001, data from the center shows.

Even areas that are wetter on average can have long dry spells, such as large areas of the eastern U.S. that have been abnormally dry this summer. Especially dry this year have been northern Louisiana, Arkansas and western Mississippi, Lawrimore said.

Other areas, such as Rhode Island and Massachusetts, have been unusually wet, and it’s been even soggier in parts of the Midwest and northern Plains.

In Iowa, it was second-wettest summer on record, and the state is coming off its wettest three-year period ever, dating back to 1873, said Harry Hillaker, a state climatologist.

Babcock said the movement of crop patterns continues a 25-year-old trend.

The warm and wet weather has been coupled with successful seed company efforts to better adapt to the changes, Babcock said.

“Plant seed companies are making more productive, short-season varieties,” he said. “It’s both climate change but also technology change.”

Brad Rippey, a U.S. Department of Agriculture meteorologist, said warming temperatures have made a big difference for crops such as corn and soybeans.