The answer may be a bit of both. Mr. DeSantis restricted visitation to nursing homes but he left early lockdown decisions to local authorities. Mayors in some hard-hit large communities shut down faster and more aggressively than the state, gaining valuable time…

A key factor, many say, is a change in the behavior of Floridians. Though the governor didn’t impose a statewide stay-at-home order until April 3, people began hunkering down en masse in mid-March, according to firms that analyze anonymous cellphone data.

That was around the same time deaths in the U.S. topped 100 and residents of New York, many of whom have ties to Florida, started staying home. The pandemic’s progression in Florida was about a week behind its trajectory in New York, so that social-distancing measures effectively kicked in earlier, said Thomas Hladish, research scientist at the University of Florida Emerging Pathogens Institute.

“In the early, exponential-growth phase of an epidemic, starting an intervention a week earlier is absolutely huge,” he said.