For about a year, Miami Dade College has offered pre-dawn classes — a scheduling feature born of necessity that nevertheless suits some students just fine. One school administrator calls it “the early bird special.”

Across town, Florida International University also has classes starting at 6 a.m., while Broward College offers early classes starting at 6:30 a.m. At least a dozen schools nationally, most of them community colleges, also open for business at 6 a.m.

The pattern has been generally the same at all these schools: student demand surged during the recession, straining the capacity of already-taxed campus buildings. Adopting unconventional hours was one of the only ways to fit additional classes in.

MDC’s Hialeah location is the most crowded of the college’s eight campuses — serving roughly 17,000 students a year through only 26 classrooms. Only the Hialeah campus and MDC’s InterAmerican campus offer 6 a.m. classes.