The night race, won by Germany's Nico Rosberg, saw an average of 73,000 spectators attend for each of the three days of the race weekend, promoter Singapore GP said.
The 2015 edition attracted about 87,000 spectators daily, while the inaugural race in 2008 welcomed over 100,000 spectators.
"The overall ticket take-up is 15 percent lower than the average attendance at the Circuit Park since the inaugural race," Singapore GP said.
The outbreak of the mosquito-borne Zika virus in the city-state had expected to have an effect on spectator numbers though many interviewed by Reuters on Friday took it in their stride.
"It's everywhere now," dancer Matt Steffanina from Los Angeles told Reuters. "We are closer to South America and Zika is way worse there, so I'm not too worried about it here."
While the additional dollars from the race itself represent a small portion of Singapore's annual tourism revenues, it marks an opportunity for Singapore to sell itself as a country that works hard and parties as hard.
Singapore's tourism receipts grew by two percent to reach S$5.4 billion (3.07 billion pounds) in the first quarter of 2016, data from the Singapore Tourism Board shows.
Rosberg celebrated his 200th Formula One race by retaking the championship lead from Mercedes team mate Lewis Hamilton after a pole to flag win on Sunday.
(Reporting by Aradhana Aravindan and Fathin Ungku; Editing by Greg Stutchbury)
