How to explain the boom in U.S. farmers markets, with three times as many operating today as a decade and a half ago? A farmer might say it's the climate, with growing conditions just right.

See also: Seven tips for shopping farmers markets.

To improve health and fitness, Americans are turning to fresher, more nutritious foods. Alarmed by food contamination scares and concerned about pesticides and additives, we want to know more about where and how food is produced. And buffeted by the down economy, we shop even more carefully for high-quality, good-value foods, preferably close to home. Meanwhile, Americans who were farming (or wanted to) looked for new ways to make a living on the land. And civic leaders searched for business enterprises that would bring development, revenue and jobs to their communities.

Enter the farmers market, with the promise of those benefits and more. In 1994, the U.S. Department of Agriculture Farmers Market Directory — the USDA's official catalog of the nation's farmers markets — listed 1,755 of them. By 2010, that number had risen to 6,132. Old, historic markets branched out to new locations; new markets sprouted in communities large and small.

Rayne Pegg, administrator of the USDA's Agricultural Marketing Service, says the creation of markets where producers sell directly to consumers has spurred "astronomical growth in local and regional foods" and created even more opportunity for farmers, ranchers and other agricultural producers. At the same time, Pegg says, the markets are "bringing fresh, healthy food to neighborhoods across the country while also strengthening local economies and building local communities."

As farmers markets across the country opened for the summer 2011 season, we scouted 12 of the most appealing. Against a field of more than 6,100, our sampling is small and necessarily subjective. But the markets listed here are proven crowd-pleasers: They regularly make the "best of" lists compiled by food writers, sustainable-farming groups and travel blogs.

Next: How to find a farmers market in your area. >>