Nine named storms formed in the Atlantic in the six-month hurricane season that ended Nov. 30, the fewest since 1997 when there were eight.
And for the first time in three years, no hurricane struck the U.S. mainland or a Caribbean island.
The nine named storms fell within the range of seven to 11 forecast by the National Oceanic and Atmospheric Administration in August.
The season had a late start, as Tropical Storm Ana formed on Aug. 11. The Atlantic season had three hurricanes; an average season has six, according to NOAA.
Of the hurricanes, Bill brushed by Bermuda and hit Newfoundland in August; Ida hit Honduras and Nicaragua in November; and Fred went nowhere in September.
Five storms swirled harmlessly in the open Atlantic. Tropical Storm Grace in September posed more of a threat to Ireland than the U.S.
The calmer season was due to the El Nino factor, a cyclical Pacific Ocean warming phenomenon that creates atmospheric conditions hostile to Atlantic hurricanes and prevents storms from strengthening, NOAA said.
Weather scientists say it is too early to tell whether El Nino will still be active for the 2010 Atlantic hurricane season. The first long-range seasonal predictions are due later this month.