The 1991 Atlantic hurricane season was a below-average Atlantic hurricane season that produced twelve tropical cyclones, of which eight strengthened to become named tropical storms; four of these became hurricanes, of which two further intensified into major hurricanes (Category 3 or higher on the Saffir–Simpson scale). The season officially began on June 1, 1991, and ended on November 30. These dates, adopted by convention, historically describe the period in each year when most subtropical or tropical cyclogenesis occurs in the Atlantic Ocean. The first system, Tropical Storm Ana, developed on July 2 while the last system, the unnamed Perfect Storm, dissipated on November 2.

The most destructive storm of the season was Hurricane Bob, which brushed the Outer Banks of North Carolina near peak intensity on August 19, then made landfall twice in Rhode Island later that day. Bob killed at least seventeen people along its path and caused extensive damage in New England, totaling $1.5 billion (1991 USD); this made it one of the ten costliest hurricanes on record for the United States at the time. The season's other significant storm was a powerful nor'easter known as the Perfect Storm. It began as an extratropical cyclone off the coast of eastern Nova Scotia late on October 28, being steered southward and then westward by a ridge to its north. Late the following day, the system absorbed Hurricane Grace to its south, contributing to substantial intensification. Its strength and large size created an enormous area of high seas over the western Atlantic Ocean during late October and early November. It caused severe coastal damage in the northeastern United States, with impacts noted as far south as Puerto Rico. Damages exceeded $200 million (1991 USD) and thirteen people were killed. Six of the fatalities occurred when the Andrea Gail and her crew were lost amidst the treacherous conditions; the events surrounding her sinking inspired Sebastian Junger's 1997 book The Perfect Storm, which was adapted into a 2000 film of the same name. As the cyclone executed a counter-clockwise loop south of New England, it gradually acquired tropical characteristics, becoming a minimal hurricane on November 1, and after weakening into a tropical storm, made landfall in Nova Scotia the next day.

This timeline documents tropical cyclone formations, strengthening, weakening, landfalls, extratropical transitions, and dissipations during the season. It includes information that was not released throughout the season, meaning that data from post-storm reviews by the National Hurricane Center, such as a storm that was not initially warned upon, has been included.

By convention, meteorologists use one time zone when issuing forecasts and making observations: Coordinated Universal Time (UTC), and also use the 24-hour clock (where 00:00 = midnight UTC). The National Hurricane Center uses both UTC and the time zone where the center of the tropical cyclone is currently located. The time zones utilized (east to west) prior to 2020 were: Atlantic, Eastern, and Central. In this timeline, all information is listed by UTC first, with the respective regional time zone included in parentheses. Additionally, figures for maximum sustained winds and position estimates are rounded to the nearest five units (knots, miles, or kilometers) and averaged over one minute, following National Hurricane Center practice. Direct wind observations are rounded to the nearest whole number. Atmospheric pressures are listed to the nearest millibar and nearest hundredth of an inch of mercury.

Timeline

June June 1 The 1991 Atlantic hurricane season officially begins. No storms formed in June.

July July 2

18:00 UTC (2:00 pm EDT) at Tropical Depression One develops from a low pressure area centered about 100 mi (155 km) south of Charleston, South Carolina.

July 4 00:00 UTC (8:00 p.m. EDT, July 3) at Tropical Depression One strengthens into Tropical Storm Ana. 06:00 UTC (2:00 a.m. EDT) at Tropical Storm Ana reaches peak winds of 50 mph (85 km/h). 18:00 UTC (2:00 p.m. EDT) at Tropical Storm Ana reaches a minimum barometric pressure of .

July 5 18:00 UTC (2:00 p.m. AST)Tropical Storm Ana becomes extratropical over the north-central Atlantic Ocean. 18:00 UTC (1:00 p.m. CDT) at Tropical Depression Two forms over the western Gulf of Mexico.

July 6 12:00 UTC (7:00 a.m. CDT) at Tropical Depression Two reaches peak winds of 35 mph (55 km/h). 22:00 UTC (5:00 p.m. CDT) at Tropical Depression Two makes landfall near La Pesca, Mexico with winds of 35 mph (55 km/h) and a barometric pressure of .

July 7 02:30 UTC (9:30 p.m. CDT, July 6) at Tropical Depression Two dissipates about 35 mi (55 km) west of La Pesca.

August August 16

00:00 UTC (8:00 p.m. EDT, August 15) at The third tropical depression of the season forms from an area of low pressure about 200 mi (325 km) east of the Bahamian capital of Nassau. 18:00 UTC (2:00 p.m. EDT) at The tropical depression strengthens into Tropical Storm Bob about 140 mi (220 km) northeast of Nassau.

August 17 18:00 UTC (2:00 p.m. EDT) at Tropical Storm Bob strengthens into a Category 1 hurricane about 235 mi (380 km) east of Daytona Beach, Florida.

August 18 18:00 UTC (2:00 p.m. EDT) at Hurricane Bob strengthens to Category 2 intensity about 265 mi (425 km) south of Norfolk, Virginia.

August 19 06:00 UTC (2:00 a.m. EDT) at Hurricane Bob strengthens to Category 3 intensity about 105 mi (165 km) east-southeast of Norfolk, Virginia, making it the first major hurricane of the season. It simultaneously reaches peak winds of 115 mph (185 km/h) and a minimum barometric pressure of . 12:00 UTC (8:00 a.m. EDT) at Hurricane Bob weakens to Category 2 intensity about 175 mi (280 km) south-southwest of Block Island, Rhode Island. 17:20 UTC (1:20 p.m. EDT) at Hurricane Bob makes its first landfall on Block Island, Rhode Island with winds of 105 mph (165 km/h) and a barometric pressure of . 18:00 UTC (2:00 p.m. EDT) at Hurricane Bob makes its second landfall in Newport, Rhode Island with winds of 100 mph (155 km/h) and a barometric pressure of .

August 20 00:00 UTC (8:00 p.m. EDT, August 19) at Hurricane Bob rapidly weakens over the Gulf of Maine, degrading into a tropical storm while centered about 35 mi (55 km) southwest of Rockland, Maine. 01:30 UTC (9:30 p.m. EDT, August 19) at Tropical Storm Bob makes its third landfall near Rockland, Maine with winds of 70 mph (110 km/h) and a barometric pressure of .

12:00 UTC (8:00 a.m. EDT) at Tropical Storm Bob emerges over the Gulf of St. Lawrence near Chatham, New Brunswick. 18:00 UTC (2:00 p.m. EDT) at Tropical Storm Bob becomes extratropical over the Gulf of St. Lawrence while centered about 190 mi (305 km) east-northeast of Chatham, New Brunswick.

August 24 06:00 UTC (2:00 a.m. AST) at Tropical Depression Four forms just to the southeast of Cape Verde. 18:00 UTC (2:00 p.m. AST) at Tropical Depression Four reaches peak winds of 35 mph (55 km/h) and a minimum barometric pressure of over southern Cape Verde.

August 26 06:00 UTC (2:00 a.m. AST)Tropical Depression Four dissipates.

August 28 12:00 UTC (8:00 a.m. AST) at Tropical Depression Five forms from an area of disturbed weather over the eastern Atlantic Ocean. 18:00 UTC (2:00 p.m. AST) at Tropical Depression Five reaches peak winds of 35 mph (55 km/h).

August 31 12:00 UTC (8:00 a.m. AST) at Tropical Depression Five dissipates several hundred miles east of the Lesser Antilles.

September September 4 12:00 UTC (8:00 a.m. AST) at A tropical depression forms from a non-tropical disturbance about 655 mi (1,055 km) southeast of Bermuda.

September 5

12:00 UTC (8:00 a.m. AST) at The tropical depression strengthens into Tropical Storm Claudette about 675 mi (1,085 km) southeast of Bermuda.

September 6 12:00 UTC (8:00 a.m. AST) at Tropical Storm Claudette strengthens into a Category 1 hurricane about 550 mi (890 km) southeast of Bermuda. 18:00 UTC (2:00 p.m. AST) at Hurricane Claudette strengthens to Category 2 intensity about 505 mi (815 km) southeast of Bermuda.

September 7 00:00 UTC (8:00 p.m. AST, September 6) at Hurricane Claudette strengthens to Category 3 intensity about 480 mi (770 km) southeast of Bermuda, making it the second major hurricane of the season. 00:00 UTC (8:00 p.m. AST, September 6) at The seventh tropical depression of the season forms from a tropical wave about 310 mi (500 km) south-southwest of Brava, Cape Verde. 10:00 UTC (6:00 a.m. AST) at Hurricane Claudette strengthens to Category 4 intensity about 415 mi (665 km) south-southeast of Bermuda. It simultaneously reaches peak winds of 130 mph (215 km/h) and a minimum barometric pressure of , making it the strongest storm of the season. 18:00 UTC (2:00 p.m. AST) at Hurricane Claudette weakens to Category 3 intensity about 350 mi (565 km) south-southeast of Bermuda.

September 8 00:00 UTC (8:00 p.m. AST, September 7) at Hurricane Claudette weakens to Category 2 intensity about 295 mi (475 km) south-southeast of Bermuda. 12:00 UTC (8:00 a.m. AST) at The seventh tropical depression of the season strengthens into Tropical Storm Danny about 760 mi (1,225 km) west-southwest of Brava, Cape Verde.

18:00 UTC (2:00 p.m. AST) at Hurricane Claudette weakens to Category 1 intensity about 125 mi (205 km) southeast of Bermuda. 18:00 UTC (2:00 p.m. AST) at Tropical Depression Eight forms from a tropical wave about midway between Hurricane Claudette and Tropical Storm Danny.

September 9 06:00 UTC (2:00 a.m. AST) at Tropical Storm Danny reaches peak winds of 50 mph (85 km/h) about 1,020 mi (1,640 km) west-southwest of Brava, Cape Verde. 18:00 UTC (2:00 p.m. AST) at Tropical Depression Eight strengthens into Tropical Storm Erika about 720 mi (1,160 km) east-southeast of Bermuda.

September 10 00:00 UTC (8:00 p.m. AST, September 9) at Tropical Storm Danny reaches a minimum barometric pressure of about 1,075 mi (1,735 km) east of Guadeloupe. 06:00 UTC (2:00 a.m. AST) at Hurricane Claudette weakens into a tropical storm about 520 mi (835 km) east of Bermuda. 12:00 UTC (8:00 a.m. AST) at Tropical Storm Erika reaches peak winds of 60 mph (95 km/h) about 1,035 mi (1,670 km) west-southwest of the Azores. 18:00 UTC (2:00 p.m. AST) at Tropical Storm Erika reaches a minimum barometric pressure of about 815 mi (1,315 km) west-southwest of the Azores.

September 11 12:00 UTC (8:00 a.m. AST) at Tropical Storm Danny weakens into a tropical depression about 225 mi (360 km) east of Guadeloupe; it dissipates six hours later.

18:00 UTC (2:00 p.m. AST) at Tropical Storm Claudette weakens into a tropical depression about 750 mi (1,205 km) west-southwest of the Azores.

September 12 03:00 UTC (11:00 p.m. AST, September 11) at Tropical Storm Erika makes landfall on the island of São Miguel in the Azores with winds of 40 mph (65 km/h) and a barometric pressure of . 06:00 UTC (2:00 a.m. AST) at Tropical Storm Erika weakens below gale force; it transitions into an extratropical cyclone within the next six hours. 18:00 UTC (2:00 p.m. AST) at Tropical Depression Claudette becomes extratropical about 410 mi (660 km) southwest of the Azores.

October October 15 00:00 UTC (8:00 p.m. EDT, October 14) at A tropical depression forms from an interaction between a cold front and a tropical wave over the northwestern Caribbean Sea. 12:00 UTC (8:00 a.m. EDT) at The tropical depression strengthens into Tropical Storm Fabian about 110 mi (175 km) southwest of the Isle of Youth in Cuba. 18:00 UTC (2:00 p.m. EDT) at Tropical Storm Fabian reaches peak winds of 45 mph (75 km/h) just to the southwest of the Isle of Youth. 21:00 UTC (5:00 p.m. EDT) at Tropical Storm Fabian makes landfall on the Isle of Youth with winds of 45 mph (75 km/h) and a barometric pressure of .

October 16