WHAT MAKES THEM hot? How about a 5,700-unit development that sails through approvals without a peep of public dissent and promises to keep you busy for the next dozen years? Perhaps it's a free-trade agreement that floods the market with professional migrants for manufacturing, health care, and higher education jobs? Could it be a 147 percent jump in building permits compared with the same quarter last year? Or maybe the distinction of being one of the country's “best quirky cities” for active retirees or among the top 25 best places to do business, as proclaimed by two leading national magazines?

For St. Louis; McAllen, Texas; Daytona Beach, Fla.; and Reno, Nev., respectively, these and other factors are what's sustaining a more-than-healthy level of housing activity and earning the envy of other areas hoping to create or sustain a similar degree of hotness.

According to extensive and ongoing research conducted by Hanley Wood Market Intelligence (formerly the Meyers Group), these markets are among the strongest in the country when it comes to housing demand, employment growth, and other “hotness” factors. “We're booming right now,” says Marcy Alamia, executive officer of the Rio Grande Valley HBA, which serves McAllen and other surrounding, equally active communities in Texas' southern tip. “There are new subdivisions going up everywhere you turn.”

Even if your definition of what's hot differs from the statistical research and anecdotal accounts gathered about these four markets, there's no doubt that each of them offers a glimpse of what drives a healthy housing economy.

Learn more about markets featured in this article: McAllen, TX, St. Louis, MO, Reno, NV, Deltona, FL.