“Considering that last year was horrific, I’m not sure exactly how much it says that it was better this year,” said the Rev. Ira Acree, who leads a church in a West Side neighborhood that has regularly been pummeled by gun violence. “But the numbers were down, and that is definitely worth something.”

Mr. Acree said he was grateful for the new police tactics. “Any type of preventive measure from the police — you’ve got to be willing to do it,” he said. “These are real lives we’re talking about.”

Among those lives affected over the weekend: A 15-year-old was shot in the back around 6:30 p.m. on Sunday on the city’s West Side when a gray sedan drove up and someone inside started firing. A 20-year-old who had severe vision problems was shot in the head and killed after playing basketball at his favorite South Side park. And in the hours before dawn on Monday, two men riding along an expressway here were shot and wounded by gunfire from another vehicle — a pattern the police have seen rise in recent years along some of the city’s busiest thoroughfares.

On Tuesday, Chicago Police officials said that while no level of violence was acceptable, they were pleased that shootings had declined. “I think we’re trending down over all,” Kevin Navarro, the first deputy superintendent, said.

Beyond a single holiday weekend, some officials say they see modest signs of improvement in recent weeks. As of Tuesday, the city had seen 235 homicides in 2017, about a 4 percent decrease from the same period a year ago. The number of shootings in Chicago has dropped by more than 14 percent, though that remains well above the counts in the nation’s two larger cities, Los Angeles and New York.