This year's North Atlantic hurricane season is forecast to be less active than usual, the US government said Wednesday.

There is a 70 percent chance of six to 11 tropical storms during the span from June 1 to November 30, the National Oceanographic and Atmospheric Administration said.

Of those, three to six could strengthen into hurricanes, including one or two of category 3, 4 or 5, with winds of at least 111 mph (178 kph).