iStock

Only 20 per­cent of U.S. companies allow staff to clock out early for "Summer Fridays," down from 63 per­cent in 2012, according to a survey of hundreds of firms. Sixty-two percent offer more flexible schedules in the summertime, down from 75 per­cent five years ago. And less than one-third of companies allow a more casual dress code during the summer — down from more than half in 2012.

But this lessened freedom during summers may lead to more flexibility all year round. "One theory is that many companies are already offering flexible schedules, remote work options, and relaxed dress codes throughout the year," said Cynthia Kong, a senior public relations manager for OfficeTeam.