LEWISTON – If last winter’s mild weather kept your snow shovel buried beneath beach towels and tanning butter, the Farmers’ Almanac recommends dusting it off this fall.

Folks from Maine to Colorado can expect heavy snow and colder-than-normal temperatures, according to this year’s edition.

“We are predicting a rough winter, with severe weather patterns that gradually shift eastward as the winter progresses,” writes Caleb Weatherbee, the pseudonym used by the almanac’s forecaster.

The 186-year-old almanac, which goes on sale Tuesday, made similar prognostications last winter. Those predictions, based on a secret model known to only two people that takes into account sunspot activity, planet position and effects of the moon, were mostly wrong.

Several feet of snow were forecast for New England, but the region had warmer-than-normal temperatures – it was the warmest winter ever recorded in Portland, Maine, and Burlington, Vt. – and a dearth of snow.

Perhaps the editors can be forgiven: Between La Ninas and El Ninos, and talk of climatic change, there has been some weird weather lately, including droughts in the United States and flooding in Europe.

The winter forecasts, which date back to Benjamin Franklin’s Poor Richard’s Almanac in the mid-1700s, have become a signpost of Americana. Fretting about their accuracy seems almost beside the point.

Editors insist the almanac’s forecast has historically been accurate about 75 percent to 80 percent of the time, even though most meteorologists say the weather cannot be predicted so far in advance.

“Once you get beyond five days, you start losing accuracy,” said Marc Spilde, a meteorologist with AccuWeather in State College, Pa. “You have to take [the almanac] with a grain of salt, basically.”

Such judgments don’t seem to faze the publication’s editor, who says long-range predictions fill an important niche.

“I think you use different forecasts for different reasons,” said editor Peter Geiger, but acknowledged: “People do judge us.”

When the Farmers’ Almanac, not to be confused with the Old Farmer’s Almanac in New Hampshire, began publishing in 1818, almanacs provided the only weather forecasts available.

Back then, the almanacs’ predictions were used mostly by farmers who sought a sense of control over crops’ fate. Nowadays, they may be used more often to pick wedding dates, Geiger said.

“We say we’re a bride’s best friend,” he said, explaining that a sunny wedding-day forecast provides peace of mind.

The 2003 Farmers’ Almanac, the first since the Sept. 11 terrorist attacks in New York and Washington, D.C., features several appeals to old-fashioned patriotism, including a list of readers’ best apple pie recipes.

Last winter, Geiger’s mother baked several of the entries and brought them to the almanac’s offices, where employee taste tests narrowed the field.