The number of arsons Sunday and the weekend was "well below" last year's number, Dan Lijana, spokesman for Mayor Dave Bing, said in a statement.
Even though fire reports increased in number as night fell, officials were happy with the less-than-expected mayhem, officials said.
"I'm thankful for the citizens coming out," The Detroit News quoted Bing as saying Sunday night as he greeted neighborhood-patrol volunteers at a fast-food restaurant in Detroit's New Center commercial and residential district.
City officials said they would release Sunday's fire numbers later Monday. They reported 18 fires Saturday night, down from the average of 26 for Saturday fires.
In 2010, there were 169 fires over a three-day period around Halloween -- up from 119 in 2009, the Detroit Free Press reported.
Angels' Night was created to lessen fires and other criminal acts associated with Detroit's Devil's Night, marked by serious vandalism and arson from the 1970s to the 1990s.
After a brutal Devil's Night in 1994, then-Mayor Dennis Archer promised city residents arson would not be tolerated. City officials organized and created Angels' Night in 1995.
As many as 40,000 residents volunteer to keep the city safe the two nights before Halloween, patrolling neighborhoods with magnetic-mount flashing amber beacons on their personal vehicles and reporting suspicious activity to police by citizens' band radios and cellphones.