Timeline of the 2021 Atlantic hurricane season

The 2021 Atlantic hurricane season was the third most active Atlantic hurricane season on record with 21 named storms, and the sixth consecutive year in which there was above-average tropical cyclone activity The season officially began on June 1, 2021, and ended on November 30, 2021. These dates, adopted by convention, historically describe the period in each year when most Northern Atlantic tropical cyclones form. However, tropical cyclone formation is possible at any time of the year, as was the case this season, when Tropical Storm Ana formed on May 22. The season's final system, Tropical Storm Wanda, dissipated on November 7. Of the season's 21 named storms, seven became hurricanes, and four further intensified into major hurricanes. The season's most devastating storm was Hurricane Ida. It made landfall in Louisiana with maximum sustained winds of 150 mph, destroying coastal communities in its path; parts of the New Orleans metropolitan area were left without power for several weeks. The storm caused an estimated $75 billion (2021 USD) in damages in the U.S. and it was responsible for 87 deaths. Over half of those deaths occurred in New York and New Jersey, as the hurricane's remnants brought rains that triggered widespread flooding throughout that region. Additionally, heavy rains caused widespread flooding and landslides across Venezuela as Ida's precursor tropical wave passed though the southeastern Caribbean Sea, resulting in at least 20 deaths. In April 2022, the name Ida was retired from reuse in the North Atlantic by the World Meteorological Organization due to the extraordinary amount of damage and number of fatalities it caused.

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) are: Greenwich, Cape Verde, 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 5 units (knots, miles, or kilometers), 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.

May
May 22
 * 06:00 UTC (2:00 a.m. AST) at 34.2°N, -62.1°W Subtropical Storm Ana forms from an extratropical cyclone about 200 mi (325 km) northeast of Bermuda.

May 23
 * 00:00 UTC (8:00 p.m. AST, May 23) at 34.7°N, -61.8°W Subtropical Storm Ana transitions to a tropical storm about 235 mi (280 km) northeast of Bermuda.
 * 06:00 UTC (2:00 a.m. AST) at 35.4°N, -61.1°W Tropical Storm Ana reaches peak intensity with winds of 45 mph (75 km/h) and a minimum central pressure of 1004 mbar, about 295 mi (470 km) northeast of Bermuda.
 * 18:00 UTC (2:00 p.m. AST) at 36.8°N, -58.7°W Tropical Storm Ana transitions to a post-tropical cyclone about 455 mi (730 km) northeast of Bermuda, and subsequently opens up into a trough.

June
June 1
 * The 2021 Atlantic hurricane season officially begins.

June 14
 * 06:00 UTC (2:00 a.m. EDT) at 33.2°N, -75.9°W Tropical Depression Two forms from a stationary front about 110 nmi east-southeast of Cape Fear, North Carolina.
 * 18:00 UTC (2:00 p.m. EDT) at 36.7°N, -69.8°W Tropical Depression Two strengthens into Tropical Storm Bill about 135 nmi east of Cape Hatteras, North Carolina.

June 15
 * 12:00 UTC (8:00 a.m. AST) at 39.4°N, -64°W Tropical Storm Bill reaches its peak intensity with maximum sustained winds of 55 kn and a minimum central pressure of 992 mbar, about 300 nmi east-southeast of Chatham, Massachusetts.

June 16
 * 00:00 UTC (8:00 p.m. AST, June 15) at 42.5°N, -57.9°W Tropical Storm Bill transitions into a post-tropical cyclone about 320 nmi east-southeast of Halifax, Nova Scotia, and later degenerates into a trough of low pressure.

June 19 June 21
 * 00:00 UTC (7:00 p.m. CDT, June 18) at °N, °W Tropical Storm Claudette forms from an area of low pressure about 80 nmi south of Morgan City, Louisiana.
 * 04:30 UTC (11:30 p.m. CDT, June 18) at °N, °W Tropical Storm Claudette makes landfall in Terrebonne Parish, Louisiana, about 25 nmi south-southwest of Houma.
 * 06:00 UTC (1:00 a.m. CDT) at °N, °W Tropical Storm Claudette reaches its peak intensity with maximum sustained winds of 40 kn and a minimum central pressure of 1003 mbar, about 8 nmi south-southwest of Houma.
 * 18:00 UTC (1:00 p.m. CDT) at °N, °W Tropical Storm Claudette weakens into a tropical depression over eastern Alabama, about 150 nmi northeast of Houma.
 * 06:00 UTC (2:00 a.m. EDT) at 35°N, -79.1°W Tropical Depression Claudette re-strengthens into a tropical storm just off the North Carolina coast.

June 22
 * 06:00 UTC (2:00 a.m. AST) at 39.7°N, -67.8°W Tropical Storm Claudette transitions to an  extratropical low, and subsequently dissipates southeast of the coast of Nova Scotia.

June 27
 * 18:00 UTC (2:00 p.m. EDT) at 29.8°N, -72.8°W – Tropical Depression Four forms from a non-tropical low about 400 nmi east-southeast of Charleston, South Carolina.

June 28
 * 06:00 UTC (2:00 a.m. EDT) at 30.7°N, -76.1°W Tropical Depression Four strengthens into Tropical Storm Danny about 225 nmi southeast of Charleston.
 * 18:00 UTC (2:00 p.m. EDT) at 32°N, -79.5°W Tropical Storm Danny reaches peak intensity with winds of 40 kn and a minimum central pressure of 1009 mbar, about 45 nmi south-southeast of Charleston.
 * 23:20 UTC (7:20 p.m. EDT) at 32.3°N, -80.5°W Tropical Storm Danny makes landfall on Pritchards Island, north of Hilton Head, South Carolina, with sustained winds of 35 kn.

June 29
 * 00:00 UTC (8:00 p.m. EDT, June 28) at 32.4°N, -80.7°W Tropical Storm Danny weakens into a tropical depression inland over eastern South Carolina, and later dissipates over eastern Georgia.

June 30
 * 18:00 UTC (2:00 p.m. AST) at 9.4°N, -42.8°W Tropical Depression Five forms from a tropical wave about 1000 nmi east-southeast of Barbados.

July
July 1
 * 00:00 UTC (8:00 p.m. AST, June 30) at 9.3°N, -45.3°W Tropical Depression Five strengthens into Tropical Storm Elsa about 850 nmi east-southeast of Barbados.

July 2
 * 12:00 UTC (8:00 a.m. AST) at 13°N, -59.8°W Tropical Storm Elsa strengthens into a Category 1 hurricane about 20 mi south of Barbados.
 * 18:00 UTC (2:00 p.m. AST) at 13.8°N, -62.4°W Hurricane Elsa reaches peak intensity with winds of 75 kn and a minimum central pressure of 991 mbar, about 95 mi west-northwest of Saint Vincent.

July 3
 * 12:00 UTC (8:00 a.m. AST) at 16.6°N, -70.3°W Hurricane Elsa weakens into a tropical storm about 100 nmi south of the southern coast of the Dominican Republic.

July 5
 * 18:00 UTC (2:00 p.m. AST) at 22.2°N, -81.6°W Tropical Storm Elsa makes landfall on the south coast of Cuba in Cienaga de Zapata National Park with maximum winds of about 55 kn.

July 7
 * 00:00 UTC (8:00 p.m. EDT, July 6) at 26.6°N, -83.2°W Tropical Storm Elsa re-strengthens into a Category 1 hurricane about 50 mi west of Englewood, Florida.
 * 06:00 UTC (2:00 a.m. EDT) at 27.8°N, -83.5°W Hurricane Elsa weakens again into a tropical storm about 35 mi west of St. Petersburg, Florida.
 * 14:30 UTC (10:30 a.m. EDT) at 29.8°N, -83.5°W Tropical Storm Elsa makes landfall in Taylor County, Florida with maximum winds of about 55 kn.

July 9
 * 15:00 UTC (11:00 a.m. EDT) at 40.9°N, -72.3°W Tropical Storm Elsa makes landfall near East Hampton, New York with maximum winds of about 50 kn.
 * 16:30 UTC (12:30 p.m. EDT) at 41.4°N, -71.7°W Tropical Storm Elsa makes landfall near Westerly, Rhode Island with maximum winds of about 50 kn.
 * 18:00 UTC (2:00 p.m. EDT) at 42°N, -71°W Tropical Storm Elsa transitions into an extratropical cyclone over southeastern New England, and later dissipates.

August
August 11
 * 00:00 UTC (8:00 p.m. AST, August 10) at 17.3°N, -66.1°W Tropical Storm Fred forms as the result of  interaction between a series of tropical waves about 50 nmi south-southeast of Ponce, Puerto Rico.
 * 17:00 UTC (1:00 p.m. AST) at 18.4°N, -70.1°W Tropical Storm Fred makes landfall near San Cristóbal, Dominican Republic, with maximum sustained winds of 40 kn.

August 12
 * 00:00 UTC (8:00 p.m. EDT, August 11) at 19.2°N, -71.7°W Tropical Storm Fred weakens to a tropical depression over central Hispaniola, 45 nmi southeast of Cap-Haïtien, Haiti.

August 13
 * 00:00 UTC (8:00 p.m. EDT, August 12) at 21.2°N, -75.5°W Tropical Depression Fred re-strengthens to a tropical storm about 50 nmi east-northeast of Holguín, Cuba.
 * 06:00 UTC (2:00 p.m. AST) at 15°N, -46.7°W Tropical Depression Seven forms from a tropical wave about 880 nmi east of the Leeward Islands.
 * 12:00 UTC (8:00 a.m. EDT) at 22°N, -77.7°W Tropical Storm Fred again weakens into a tropical depression as it simultaneously makes landfall on Cayo Romano, on the northern coast of Cuba.

August 14
 * 00:00 UTC (8:00 a.m. EDT, August 13) at 22.5°N, -80.2°W Tropical Depression Fred degenerates into an open trough over central Cuba.
 * 12:00 UTC (8:00 a.m. AST) at 16.1°N, -57.2°W Tropical Depression Seven strengthens into Tropical Storm Grace about 270 nmi east-southeast of the Leeward Islands.

August 15 August 16
 * 00:00 UTC (8:00 p.m. AST, August 14) at 16.5°N, -61.7°W Tropical Storm Grace weakens into a tropical depression about 35 mi north of Guadeloupe.
 * 12:00 UTC (8:00 a.m. EDT) at 25.7°N, -84.7°W Remnants of Fred re-develop into a tropical storm about 160 nmi west of Naples, Florida.
 * 18:00 UTC (2:00 p.m. AST) at 34.1°N, -62.7°W Tropical Depression Eight forms from a surface low pressure system about 150 nmi northeast of Bermuda.
 * 12:00 UTC (8:00 a.m. AST) at 17.5°N, -71.4°W Tropical Depression Grace re-strengthens into a tropical storm about 40 nmi east of Beata Island, Dominican Republic.
 * 16:30 UTC (12:30 p.m. AST) at 17.7°N, -71.4°W Tropical Storm Grace makes landfall just south of Oviedo, Dominican Republic, with sustained winds of 35 kn.
 * 18:00 UTC (1:00 p.m. CDT) at 29.5°N, -85.4°W Tropical Storm Fred reaches peak intensity with maximum sustained winds of 55 kn and a minimum central pressure of 991 mbar, about 25 nmi southwest of Apalachicola, Florida.
 * 18:00 UTC (2:00 p.m. AST) at 31.1°N, -62.9°W Tropical Depression Eight strengthens into Tropical Storm Henri 110 nmi southeast of Bermuda.
 * 19:00 UTC (2:00 p.m. CDT) at 29.7°N, -85.4°W Tropical Storm Fred makes landfall at peak intensity on the St. Joseph Peninsula, just northwest of Cape San Blas, in the Florida Panhandle.

August 17
 * 12:00 UTC (8:00 a.m. EDT) at 32.8°N, -85.2°W Tropical Storm Fred weakens to a tropical depression over eastern Alabama.
 * 14:00 UTC (10:00 a.m. EDT) at 18.2°N, -76.6°W Tropical Storm Grace makes landfall on the northeastern coast of Jamaica near Black Hill, with sustained winds of 50 kn.

August 18
 * 00:00 UTC (8:00 p.m. EDT, August 17) at 35.9°N, -83.6°W Tropical Storm Fred becomes a post-tropical low over eastern Tennessee.
 * 12:00 UTC (8:00 a.m. EDT) at 19.2°N, -81.5°W Tropical Storm Grace strengthens into a Category 1 hurricane about 15 nmi west-southwest of Grand Cayman.

August 19
 * 00:00 UTC (8:00 p.m. EDT, August 18) at 41.2°N, -78.2°W Post-Tropical Cyclone Fred becomes an extratropical low over central Pennsylvania, and subsequently dissipates.
 * 09:45 UTC (4:45 a.m. CDT) at 20.1°N, -87.5°W Hurricane Grace makes landfall about 10 mi south of Tulum, Quintana Roo, with sustained winds of 75 kn.
 * 12:00 UTC (7:00 a.m. CDT) at 20.2°N, -88.1°W Hurricane Grace weakens into a tropical storm inland over the Yucatán Peninsula.

August 20
 * 12:00 UTC (7:00 a.m. CDT) at 20.6°N, -93.8°W Tropical Storm Grace re-strengthens into a Category 1 hurricane about 205 nmi east-southeast of Tuxpan, Veracruz.
 * 18:00 UTC (1:00 p.m. CDT) at 20.6°N, -94.7°W Hurricane Grace intensifies to Category 2 strength about 155 nmi east-southeast of Tuxpan.

August 21
 * 00:00 UTC (7:00 p.m. CDT, August 20) at 20.7°N, -95.8°W Hurricane Grace intensifies to Category 3 strength about 90 nmi east of Tuxpan, and simultaneously reaches peak intensity with winds of 105 kn and a minimum central pressure of 967 mbar.
 * 05:30 UTC (12:30 a.m. CDT) at 20.6°N, -97.1°W Hurricane Grace makes landfall near Tecolutla, Veracruz, at peak intensity.
 * 12:00 UTC (7:00 a.m. CDT) at 20.2°N, -98°W Hurricane Grace weakens to a tropical storm about 60 nmi southwest of Tuxpan, and the surface circulation later dissipates.
 * 12:00 UTC (8:00 a.m. EDT) at 33.6°N, -72.7°W Tropical Storm Henri strengthens into a Category 1 hurricane about 170 nmi southeast of Cape Hatteras, North Carolina.

August 22
 * 06:00 UTC (2:00 a.m. EDT) at 39.4°N, -71°W Hurricane Henri reaches peak intensity with maximum sustained winds of 65 kn and a minimum central pressure of 986 mbar, about 111 nmi south-southeast of Block Island, Rhode Island.
 * 12:00 UTC (8:00 a.m. EDT) at 40.7°N, -71.3°W Hurricane Henri weakens into a tropical storm, about 33 nmi south-southeast of Block Island.
 * 15:20 UTC (11:20 a.m. EDT) at 41.2°N, -71.6°W Tropical Storm Henri makes landfall on Block Island with sustained winds of 55 kn.
 * 16:15 UTC (12:15 p.m. EDT) at 41.3°N, -71.8°W Tropical Storm Henri makes landfall near Westerly, Rhode Island with sustained winds of 55 kn.

August 23
 * 00:00 UTC (8:00 p.m. EDT, August 22) at 41.8°N, -73°W Tropical Storm Henri weakens into a tropical depression about 62 nmi northwest of Westerly.
 * 18:00 UTC (2:00 p.m. EDT) at 41.5°N, -73.8°W Tropical Depression Henri degenerates into a remnant low about 91 nmi northwest of Westerly, and subsequently dissipates.

August 26
 * 15:00 UTC (11:00 a.m. EDT) at 16.9°N, -79.2°W Tropical Depression Nine forms from a combination of multiple low-latitude weather systems, starting with a tropical wave, about 150 nmi  southwest of Kingston,Jamaica.
 * 18:00 UTC (6:00 p.m. EDT) at 17.4°N, -79.5°W Tropical Depression Nine strengthens into Tropical Storm Ida about 170 nmi west of Kingston.

August 27
 * 18:00 UTC (2:00 p.m. EDT) at 21.5°N, -82.6°W Tropical Storm Ida strengthens into a Category 1 hurricane as it makes landfall on Isla de la Juventud, Cuba.
 * 23:25 UTC (7:25 p.m. EDT) at 22.4°N, -83.2°W Hurricane Ida makes landfall near Playa Dayaniguas, in Pinar del Río Province, Cuba, with sustained winds of 70 kn.

August 28
 * 06:00 UTC (2:00 a.m. AST) at 13.7°N, -49.8°W Tropical Depression Ten forms from a tropical wave about 700 nmi east of the Leeward Islands.
 * 18:00 UTC (2:00 p.m. AST) at 32.2°N, -51°W Tropical Depression Eleven forms from a tropical wave about 700 nmi east of Bermuda.

August 29
 * 00:00 UTC (7:00 p.m. CDT, August 28) at 26.7°N, -87.6°W Hurricane Ida intensifies to Category 2 strength about 250 nmi southeast of Houma, Louisiana.
 * 06:00 UTC (1:00 a.m. CDT) at 27.6°N, -88.7°W Hurricane Ida intensifies to Category 4 strength about 160 nmi southeast of Houma.
 * 06:00 UTC (2:00 a.m. AST) at 33.5°N, -49.3°W Tropical Depression Eleven strengthens into Tropical Storm Julian about 775 nmi east of Bermuda.
 * 12:00 UTC (7:00 a.m. CDT) at 28.5°N, -89.6°W Hurricane Ida reaches peak intensity with maximum sustained winds of 130 kn and a minimum central pressure of 929 mbar, about 50 mi (85 km) southwest of the mouth of the Mississippi River.
 * 16:55 UTC (11:55 a.m. CDT) at 29.1°N, -90.2°W Hurricane Ida makes landfall at Port Fourchon, Louisiana, with sustained winds of 130 kn.

August 30
 * 00:00 UTC (7:00 p.m. CDT, August 29) at 29.9°N, -90.6°W Hurricane Ida weakens to Category 2 strength inland, about 20 nmi west-southwest of New Orleans, Louisiana.
 * 06:00 UTC (1:00 a.m. CDT) at 30.6°N, -90.8°W Hurricane Ida weakens to Category 1 strength about 20 mi (30 km) south-southwest of Greensburg, Louisiana.
 * 06:00 UTC (6:00 a.m. GMT) at 38.9°N, -40°W Tropical Storm Julian reaches peak intensity with  maximum sustained winds of 50 kn and a minimum central pressure of 993 mbar.
 * 06:00 UTC (2:00 a.m. AST) at 20.5°N, -50.6°W Tropical Depression Ten strengthens into Tropical Storm Kate.
 * 12:00 UTC (7:00 a.m. CDT) at 31.5°N, -90.9°W Hurricane Ida weakens into a tropical storm about 55 nmi south-southwest of Jackson, Mississippi.
 * 12:00 UTC (12:00 a.m. GMT) at 40.6°N, -37.9°W Tropical Storm Julian completes extratropical transition and merges with a frontal system about 750 nmi east-southeast of Cape Race, Newfoundland.
 * 12:00 UTC (8:00 a.m. AST) at 21.3°N, -50.8°W Tropical Storm Kate reaches peak intensity with  maximum sustained winds of 40 kn and a minimum central pressure of 1004 mbar, about 670 nmi east-northeast of the Leeward Islands.

August 31
 * 00:00 UTC (7:00 p.m. CDT, August 30) at 33°N, -90°W Tropical Storm Ida weakens into a tropical depression about 40 nmi north of Jackson.
 * 12:00 UTC (8:00 a.m. AST) at 23.2°N, -50.9°W Tropical Storm Kate weakens into a tropical depression.
 * 18:00 UTC (5:00 p.m. CVT) at 11.5°N, -20.6°W Tropical Depression Twelve forms from a tropical wave about 280 nmi south-southeast of the Cabo Verde Islands.

September
September 1
 * 00:00 UTC (11:00 p.m. CVT, August 31) at 11.9°N, -22.5°W Tropical Depression Twelve strengthens into Tropical Storm Larry about 200 nmi south-southeast of the Cabo Verde Islands.
 * 12:00 UTC (8:00 a.m. EDT) at 37.7°N, -81.5°W Tropical Depression Ida transitions into an extratropical low over southern West Virginia, and subsequently degenerates to a trough.
 * 12:00 UTC (8:00 a.m. AST) at 26.6°N, -52.3°W Tropical Depression Kate degenerates into an elongated trough about 835 nmi northeast of the northern Leeward Islands, and subsequently dissipates.

September 2
 * 06:00 UTC (2:00 a.m. AST) at 13°N, -31.6°W Tropical Storm Larry strengthens into a Category 1 hurricane about 425 nmi west-southwest of the westernmost Cabo Verde Islands.

September 3
 * 18:00 UTC (2:00 p.m. AST) at 14.7°N, -41.4°W Hurricane Larry intensifies to Category 2 strength about 1055 nmi east of the Leeward Islands.

September 4
 * 00:00 UTC (8:00 p.m. AST, September 3) at 16.3°N, -44.6°W Hurricane Larry intensifies to Category 3 strength about 980 nmi east of the Leeward Islands.

September 5
 * 12:00 UTC (8:00 a.m. AST) at 19.2°N, -49.4°W Hurricane Larry reaches peak intensity with winds of 110 kn and a minimum central pressure of 953 mbar, about 725 nmi east of the Leeward Islands.

September 7
 * 12:00 UTC (8:00 a.m. AST) at 24°N, -55.4°W Hurricane Larry weakens to Category 2 strength about 700 nmi southeast of Bermuda.

September 8
 * 18:00 UTC (1:00 p.m. CDT) at 28.4°N, -86.8°W Tropical Storm Mindy forms from a tropical wave about 140 nmi southwest of Apalachicola, Florida.

September 9
 * 01:15 UTC (8:15 p.m. CDT, September 8) at 29.7°N, -85.1°W Tropical Storm Mindy reaches peak intensity with maximum sustained winds of 50 kn and a minimum central pressure of 1000 mbar, while simultaneously making landfall on St. Vincent Island, Florida, about 10 nmi west-southwest of Apalachicola.
 * 06:00 UTC (2:00 a.m. EDT) at 30.1°N, -60.8°W Hurricane Larry weakens to Category 1 strength about 240 nmi southeast of Bermuda.
 * 12:00 UTC (8:00 a.m. EDT) at 31.2°N, -81.8°W Tropical Storm Mindy weakens into a tropical depression over southeast Georgia.

September 10
 * 00:00 UTC (8:00 p.m. EDT, September 9) at 32.1°N, -76.8°W Tropical Depression Mindy transitions into a post-tropical cyclone offshore over Atlantic Ocean, about 150 nmi southeast of Wilmington, North Carolina, and later dissipates.

September 11
 * 03:30 UTC (11:30 p.m. AST, September 10) at 47.3°N, -54.6°W Hurricane Larry makes landfall near Great Bona Cove, along the south shore of Newfoundland's Burin Peninsula, with sustained winds of 70 kn.
 * 12:00 UTC (8:00 a.m. AST) at 52.5°N, -49.7°W Hurricane Larry becomes an extratropical cyclone about 320 nmi north-northeast of St. John's, Newfoundland and Labrador, and is later absorbed by larger extratropical low.

September 12
 * 12:00 UTC (7:00 a.m. CDT) at 21°N, -95.2°W Tropical Storm Nicholas forms from a tropical wave about 115 nmi northeast of Veracruz,Veracruz.

September 14
 * 00:00 UTC (7:00 p.m. CDT, September 13) at 28°N, -96.2°W Tropical Storm Nicholas strengthens into a Category 1 hurricane about 25 nmi south-southwest of Matagorda, Texas, and simultaneously reaches peak intensity with maximum sustained winds of 65 mph and a minimum central pressure of 988 mbar.
 * 05:30 UTC (12:30 a.m. CDT) at 28.7°N, -95.7°W Hurricane Nicholas makes landfall on the eastern portion of the Matagorda Peninsula, less than 10 nmi west-southwest of Sargent Beach, Texas, with maximum sustained winds of 65 mph.
 * 12:00 UTC (7:00 a.m. CDT) at 29.3°N, -95.4°W Hurricane Nicholas weakens into a tropical storm about 25 nmi south-southwest of Houston, Texas.

September 15
 * 00:00 UTC (7:00 p.m. CDT, September 14) at 29.9°N, -94.4°W Tropical Storm Nicholas weakens into a tropical depression about 20 nmi west of Port Arthur, Texas.
 * 18:00 UTC (1:00 p.m. CDT) at 30.2°N, -92.4°W Tropical Depression Nicholas degenerates into a remnant low about 20 nmi west of Lafayette, Louisiana, and subsequently dissipates.

September 17
 * 18:00 UTC (2:00 p.m. EDT) at 35.9°N, -72.7°W Tropical Storm Odette forms from a surface trough associated with a mid- to upper-level low about 150 nmi east of the North Carolina–Virginia border.

September 18
 * 06:00 UTC (2:00 a.m. AST) at 37.6°N, -70.1°W Tropical Storm Odette reaches peak intensity with maximum winds of 40 kn and a minimum central pressure of 1005 mbar.
 * 12:00 UTC (8:00 a.m. AST) at 38.3°N, -68.3°W Tropical Storm Odette transitions into an extratropical cyclone about 250 nmi east-southeast of Atlantic City, New Jersey, and subsequently opens up into a trough.

September 19
 * 00:00 UTC (8:00 p.m. AST, September 18) at 16.4°N, -52.7°W Tropical Depression Sixteen forms about from a tropical wave about 525 nmi east of the northern Leeward Islands.
 * 00:00 UTC (11:00 p.m. CVT, September 18) at 10.4°N, -27.4°W Tropical Depression Seventeen forms from a tropical wave about 325 nmi south-southwest of the southernmost Cabo Verde Islands.
 * 06:00 UTC (2:00 a.m. AST) at 16.8°N, -54.4°W Tropical Depression Sixteen strengthens into Tropical Storm Peter about 425 nmi east of the Leeward Islands.
 * 18:00 UTC (2:00 p.m. AST) at 17.9°N, -57°W Tropical Storm Peter attains its peak intensity with maximum sustained winds of 45 kn and a minimum central pressure of 1005 mbar, about 280 nmi east of the northern Leeward Islands.
 * 18:00 UTC (5:00 p.m. CVT) at 13.8°N, -29.4°W Tropical Depression Seventeen strengthens into Tropical Storm Rose about 300 nmi west of the southernmost Cabo Verde Islands.

September 21
 * 00:00 UTC (8:00 p.m. AST, September 20) at 18.8°N, -35.3°W Tropical Storm Rose attains its peak intensity with maximum sustained winds of 50 kn and a minimum central pressure of 1004 mbar, about 590 nmi west-northwest of the Cabo Verde Islands.
 * 18:00 UTC (2:00 p.m. AST) at 20.2°N, -64.6°W Tropical Storm Peter weakens to a tropical depression, about 115 nmi north of Saint Thomas, United States Virgin Islands, and later degenerates into a surface trough.

September 22
 * 06:00 UTC (2:00 a.m. AST) at 23.1°N, -38.1°W Tropical Storm Rose weakens into a tropical depression 815 nmi west-northwest of the Cabo Verde Islands.
 * 12:00 UTC (8:00 a.m. AST) at 23.4°N, -38.8°W Tropical Depression Rose degenerates into a remnant low about 850 nmi west-northwest of the Cabo Verde Islands, and subsequently opens up into a trough of low pressure.
 * 18:00 UTC (2:00 p.m. AST) at 10°N, -33.1°W Tropical Depression Eighteen forms from a tropical wave about 575 nmi west-southwest of the southernmost Cabo Verde Islands.

September 23
 * 06:00 UTC (2:00 a.m. AST) at 10.4°N, -36°W Tropical Depression Eighteen strengthens into Tropical Storm Sam.

September 24
 * 06:00 UTC (2:00 a.m. AST) at 11.4°N, -41.6°W Tropical Storm Sam strengthens into a Category 1 hurricane about 1100 nmi east of the Windward Islands.
 * 06:00 UTC (2:00 a.m. AST) at 31.4°N, -62°W A subtropical depression forms from a non-tropical area of disturbed weather about 150 nmi east-southeast of Bermuda.
 * 12:00 UTC (8:00 a.m. AST) at 32.8°N, -62.9°W The subtropical depression strengthens into Subtropical Storm Teresa about 110 mi (175 km) east of Bermuda.
 * 18:00 UTC (2:00 p.m. AST) at 33.6°N, -64.1°W Subtropical Storm Teresa reaches its peak intensity with maximum sustained winds of 40 kn and a minimum central pressure of 1008 mbar about 90 mi (145 km) north of Bermuda.

September 25
 * 00:00 UTC (8:00 p.m. AST, September 24) at 12.3°N, -45.4°W Hurricane Sam intensifies to Category 2 strength.
 * 12:00 UTC (8:00 a.m. AST) at 12.8°N, -47.2°W Hurricane Sam intensifies to Category 3 strength.
 * 12:00 UTC (8:00 a.m. AST) at 34.3°N, -65.2°W Subtropical Storm Teresa weakens into a subtropical depression about 135 mi (220 km) north of Bermuda.
 * 18:00 UTC (2:00 p.m. AST) at 13.1°N, -48.1°W Hurricane Sam intensifies to Category 4 strength.
 * 18:00 UTC (2:00 p.m. AST) at 34.3°N, -64.5°W Subtropical Depression Teresa degenerates into a remnant low about 135 mi (215 km) north of Bermuda, and subsequently dissipates.

September 26
 * 18:00 UTC (2:00 p.m. AST) at 14.1°N, -50.3°W Hurricane Sam reaches its peak intensity with maximum sustained winds of 135 kn and a minimum central pressure of 927 mbar, about 600 nmi east of the Lesser Antilles.

September 27
 * 12:00 UTC (8:00 a.m. AST) at 15.4°N, -51.7°W Hurricane Sam weakens to Category 3 strength.

September 28
 * 06:00 UTC (2:00 a.m. AST) at 16.9°N, -53.5°W Hurricane Sam re-intensifies to Category 4 strength.

September 29
 * 12:00 UTC (11:00 a.m. CVT) at 7.8°N, -24.1°W Tropical Depression Twenty forms from a tropical wave about 465 nmi south of the Cabo Verde Islands.
 * 18:00 UTC (5:00 p.m. CVT) at 8.1°N, -25.1°W Tropical Depression Twenty strengthens into Tropical Storm Victor south of the Cabo Verde Islands.

October
October 1
 * 06:00 UTC (2:00 a.m. AST) at 25.8°N, -61.6°W Hurricane Sam reaches a secondary peak intensity, with winds of 130 kn and a minimum central pressure of 936 mbar about 425 nmi south-southeast of Bermuda.
 * 12:00 UTC (8:00 a.m. AST) at 11.4°N, -33°W Tropical Storm  Victor reaches peak intensity with  maximum sustained winds of 55 kn and a minimum central pressure of 997 mbar, about 600 nmi west-southwest of the Cabo Verde Islands.

October 2
 * 18:00 UTC (2:00 p.m. AST) at 34.7°N, -59.1°W Hurricane Sam weakens to Category 3 strength about 315 nmi east-northeast of Bermuda.
 * 18:00 UTC (2:00 p.m. AST) at 13.5°N, -37.7°W Tropical Storm Victor weakens to a tropical depression about 825 nmi west of the Cabo Verde Islands.

October 3
 * 06:00 UTC (2:00 a.m. AST) at 36.7°N, -56.6°W Hurricane Sam weakens to Category 2 strength about 480 nmi northeast of Bermuda.

October 4
 * 12:00 UTC (8:00 a.m. AST) at 17.8°N, -43.1°W Tropical Depression Victor degenerates into a trough more than 1200 nmi west of the Cabo Verde Islands, and later dissipates.
 * 18:00 UTC (6:00 p.m. GMT) at 43.8°N, -43.6°W Hurricane Sam weakens to Category 1 strength about 435 nmi southeast of Cape Race, Newfoundland.

October 5
 * 06:00 UTC (6:00 a.m. GMT) at 49.4°N, -39.7°W Hurricane Sam transitions to a post-tropical cyclone about 565 nmi east of Cape Race, and subsequently merges with another extratropical low.

October 30
 * 12:00 UTC (8:00 a.m. AST) at 38.5°N, -49.6°W Subtropical Storm Wanda forms from a nor'easter about 515 nmi south-southeast of Cape Race, Newfoundland.

October 31
 * 12:00 UTC (12:00 p.m. GMT) at 36.5°N, -43.4°W Subtropical Storm Wanda attains its peak intensity with maximum sustained winds of 50 kn and a minimum central pressure of 983 mbar, about 785 nmi west of the Azores.

November
November 1
 * 12:00 UTC (12:00 p.m. GMT) at 34.1°N, -43.4°W Subtropical Storm Wanda transitions to a tropical storm about 825 nmi west-southwest of the Azores.

November 7
 * 12:00 UTC (12:00 p.m. GMT) at 39.2°N, -34.9°W Tropical Storm Wanda transitions to a post-tropical cyclone about 375 nmi west-northwest of the Azores, and later dissipates.

November 30
 * The 2021 Atlantic hurricane season officially ends.