LEWISTON, Maine (AP) - Americans should double-check their supply of long johns and sweaters for the winter ahead, which the Farmers' Almanac predicts will be colder than usual across three-fourths of the nation.

But people who put their stock in the more scientific-based National Weather Service might want to think twice, with the weather service calling for a warmer-than-normal winter.

The almanac's 2010 edition, which goes on sale Tuesday, says numbingly cold temperatures will predominate in the country's midsection, from the Rocky Mountains in the West to the Appalachians in the East.

"Basically we're saying it's going to be an ice cold sandwich," said managing editor Sandi Duncan. "We feel the middle part of the country's really going to be cold - very very cold, very very frigid, with a lot of snow. On the east and west coasts, it's going to be a little milder. Not to say it's going to be a mild short winter, but it'll be milder compared to the middle of the country."

The Farmers' Almanac, which has been published since 1818, issues annual forecasts that are spelled out in three- and four-day increments broken down into seven regions. The almanac claims an 80 to 85 percent accuracy rate, but many people read the forecasts only in fun.

This winter, the 200-page publication says it'll be cool and snowy in the Northeast, bitterly cold and dry in the Great Lakes states, and cold and snowy across North Central states. The Northwest will be cool with average precipation, the Southwest will be mild and dry, the South Central states will be cold and wet and the Southeast will be mild and dry.

The forecasts are prepared two years in advance and are based on a secret formula using sun spots, planet positions and the effects of the moon, said editor Peter Geiger.

The almanac's forecast is at odds with the National Weather Service's long-range outlook for the meteorological winter, from December through February.

The weather service is calling for warmer-than-normal temperatures across much of the country because of an El Nino weather system that has developed in the tropical Pacific Ocean, said Mike Halpert, deputy director of the NOAA Climate Prediction Center in Camp Springs, Md.

"The stronger El Nino becomes, the more confident and the more likely it will be the northern part of the country will have a milder than average winter," Halpert said.

As for precipitation, the El Nino conditions have forecasters predicting wet winter conditions along the southern tier of the U.S., with dry conditions in the Northwest and the Ohio Valley.

The climate prediction center issues long-range forecasts up to a year out, but it's hard to be accurate that far out because of unforeseen variables. As for almanacs, "We view them more as entertainment than as science," Halpert said.

Geiger stands by his almanac's forecasts, saying they have "stood the test of time." The 2009 edition accurately predicted last winter's cold conditions and the extreme rains that the Northeast got in June and July, he said.

"We don't hit every darn day, but we're pretty darn accurate," Geiger said. "People use us all the time to plan weddings and vacations."

The Farmer's Almanac, not to be confused with the New Hampshire-based Old Farmer's Almanac, has a circulation of about 3.5 million, Geiger said. Besides weather forecasts, it features a mix of helpful hints, recipes, gardening tips, anecdotes, jokes and inspirational message.

This year's edition focuses on the environment and on money matters. It features articles on how to make do with less, how to stretch your meal money and how to get back to the land.

But it's the weather forecasts that draw people to the almanac.

"Already I'm getting peppered with 'Should I lock in my heating oil costs? Should I buy a shovel? Should I do this, should I do that?'" Geiger said.

As for next summer, the almanac is calling for hotter-than-usual conditions across most of the country.

And the National Weather Service? Its long-range summer forecast also predicts that much of the country will be hotter than normal.