An average of 5.9 hurricanes form in the Atlantic each year.
"The Atlantic is a bit warmer than in the past couple of years," said Phil Klotzbach, a member of the forecast team. "That is something we would like to keep an eye on."
Gray had projected seven hurricanes with three major storms in a preliminary forecast in December.
One of the most closely watched hurricane forecasters, Gray has been issuing hurricane predictions for more than 20 years. But he and others have been criticized in recent years for having forecasts that were off the mark.
Gray's team says precise predictions are impossible, and the warnings raise awareness of hurricanes.
"We have not been ashamed of our forecast failures. It is the nature of seasonal forecasting to sometimes be wrong," Klotzbach said in a telephone interview from the Bahamas, where the team announced the forecast at a weather conference.
The 2007 Atlantic season saw 15 named storms, six of which became hurricanes. Two were major storms.
Before the June-November season, U.S. government scientists predicted 13 to 17 named storms and six hurricanes, three to five major. Gray was further off, forecasting 17 named storms, including nine hurricanes, five of them major.
U.S. government forecasters issue their seasonal outlook in late May.
National Hurricane Center director Bill Read, who is in his first year on the job, has said he would prefer to characterize the season in general terms -- as above average, average or below average -- instead of trying to forecast a precise number of storms.
"It doesn't matter what the numbers are," center spokesman Dennis Feltgen said Wednesday, repeating a center mantra that it takes only one powerful storm to make it a bad season.