Humberto has strengthened from a tropical storm to be a Category 1 hurricane — the first of the 2013 Atlantic season — the National Hurricane Center said early Wednesday.
Humberto's maximum sustained winds were near 75 mph, just above the 74 mph level that promotes it to a hurricane from a tropical storm.
The NHC said Humberto could gain more strength before weakening on Thursday.
It's unusually late for the season's first hurricane to develop. The first hurricane typically forms on Aug. 10, according to the hurricane center.
Humberto fell just three hours short of being the latest in the season that the first hurricane has developed, the Weather Channel reported. The record is still held by Hurricane Gustav in 2002.
Humberto is currently centered about 310 miles west-northwest of the southernmost Cape Verde Islands, in the eastern Atlantic, and is moving north-northwest near 8 mph.
It poses no threat to land.
Separately, Tropical Storm Gabrielle passed west-southwest of Bermuda, hitting the wealthy British territory with wind, rain and rough surf.
Gabrielle has maximum sustained winds near 50 mph.