Almanac begins third century of know-and-tell : The farmer’s friend blends weather forecasts with folk humor and fun facts. Its mix is right on the money.

Here are some things you might like to know: California can expect heavy rain and snow the last week of March. Eating chocolate doesn’t cause pimples. You can have a star named after you for $40. Leeches may be repugnant, but they’ve become a valuable source of biological insights in the laboratory.

If all this is news, then you apparently haven’t read the 1993 edition of the Old Farmer’s Almanac, the venerable publication that for 201 years has been dispensing weather forecasts a year in advance (accuracy is 80%, the editors say), nostalgia, homespun humor, folklore and arcane tidbits to millions of Americans.

The Almanac, the nation’s oldest continuous periodical, is published in a red clapboard building here on Main Street. And if you ask its owner-editor, Judson Hale, what the Almanac’s secret of longevity and success is--circulation is 4.5 million, an all-time high; profit margins regularly run at 15% to 20%--he’ll mention the strength of tradition and familiarity. After all, the Old Farmer’s Almanac has had only four owners and 12 editors since 1772 and hasn’t even changed its cover design since 1851.

Hale, who would have been a member of Dartmouth College’s 1955 class had he not thrown up on the dean just before graduation, has, like the Almanac itself, an easy, irreverent manner that is part tweed-jacket urbanity, part bib-overall folksiness. Once asked on a radio talk show if it was true that New Englanders are aloof and cold, he replied: “Mind your own business.”

In his cluttered office, surrounded by a stuffed chicken, photos of Chief Sitting Bull and enough memorabilia to fill an antique shop, Hale thumbed through the yellow-jacketed Almanac. “If you wanted to categorize the Almanac,” he said, “I think you’d say it’s useful, informative, a little wacky. We look for balance. If you think the Almanac is totally comical, you’re missing the point. And if you think it’s totally serious, you’re missing the point too.”

Sprinkled among well-crafted essays and feature stories in past years have been articles on how to build a bat house (bats are voracious mosquito eaters), the three best ways to hypnotize your chickens (the farmer-author never explained why you’d want to hypnotize your chickens), instructions on how to cook an ostrich (a 100-pound bird needs six pounds of onions, three bunches of parsley and plenty of salt and pepper) and advice, in 1877, on how to make your husband happy (“Try to do only what your husband wishes in the household . . .”).

But at the heart of the Almanac, ever since Robert B. Thomas sold the first edition in Boston for 6 pence (about 9 cents), are the weather forecasts and the astronomical and astrological data that tell about the movement of the tides, the moon and the forces that, many believe, dictate everything from the best time to plant your corn to the optimum moment to castrate your bull or have surgery. In all this, there is the unspoken, somehow comforting message that our lives are subject to repeated patterns and a universal order.

“The Almanac,” Franklin D. Roosevelt said in 1938, “is one of those institutions which is perennially young in the appeal which it makes. From long custom we depend on it. It is an invaluable friend.”

No doubt a coincidence, but four years after Roosevelt’s remark, the FBI arrested a German spy who had landed on Long Island in a U-boat. In his coat pocket was the Old Farmer’s Almanac, which, the government speculated, he may have wanted because of the weather forecasts. The story comes as no surprise to the Almanac’s current managing editor, Susan Peery: On several occasions, young women have tried to bribe her for as-yet-unpublished weather forecasts before choosing a wedding date.

Robert B. Thomas’ “secret weather formula” rests in a locked tin box in the Almanac’s offices. It’s still in use, although the Almanac’s present forecaster, Richard Head, a former NASA meteorologist who studies solar cycles and weather patterns, relies more on science than folklore and isn’t much concerned with the fact that “asses hanging their ears forward . . . prognosticate rain.”

As far as anyone on the Almanac’s six-person, full-time staff can figure out, the publication only lost money once, in 1938 when forecasts were dropped from the edition. Three years later, Hale’s uncle, Robb Sagendorph, bought the Almanac from Little, Brown & Co. after two “stiff martinis.” Hale, who says he got his job through nepotism, became the editor in 1971.

Except for 175 lifetime subscriptions ($75 each), the Almanac’s circulation comes entirely from street sales. Of the 1994 edition and the years beyond, executive editor Tim Clark, who studied folklore at Harvard, says: “We’re in a situation now where our main task is not to screw up.”