The season featured 17 named storms, 10 hurricanes, and 6 major hurricanes, making the season the sixth-most active Atlantic hurricane season on record, tied with 1936 .
Unlike the pattern of previous years that acted to steer many tropical cyclones harmlessly into the open Atlantic, 2017 featured a pattern conducive for landfalls; in fact, the season culminated into 23 separate landfalls by Atlantic named storms. At least 3,364 fatalities were recorded and damage totaled $294.92 billion, cementing the 2017 season as the costliest in recorded history and the deadliest season since 2005.
On September 12, a well-defined tropical wave emerged into the Atlantic from the west coast of Africa. The wave initially produced disorganized and scattered deep convection as it moved westward. However, by September 15, convective activity increased and became more organized, including the development of curved cloud bands. Around 12:00 UTC on the following day, a tropical depression formed approximately 665 mi (1,070 km) east of Barbados. Six hours later, the depression intensified into Tropical Storm Maria. The cyclone moved west-northwestward and strengthened into a hurricane around 18:00 UTC on September 17. Thereafter, warm sea-surface temperatures and light wind shear allowed Maria to intensify rapidly. By 12:00 UTC on September 18, Maria became a major hurricane upon reaching Category 3 status. Just 12 hours later, the cyclone became a Category 5 hurricane while nearing Dominica. At 01:15 UTC on September 19, Maria struck the island with winds of 165 mph (270 km/h). The storm briefly weakened to Category 4 status by the time it reached the Caribbean, but re-strengthened to a Category 5 hurricane later on September 19. At 03:00 UTC the next day, Maria peaked with sustained winds of 175 mph (280 km/h) and a barometric pressure of 908 mbar (26.8 inHg).
Most of the deaths from this season occurred from Maria. In early October, Hurricane Nate became the fastest-moving tropical cyclone in the Gulf of Mexico on record and the third hurricane to strike the contiguous United States in 2017.
Slightly over a week later, Hurricane Ophelia became the easternmost major hurricane in the Atlantic basin on record, and later impacted most of northern Europe as an extratropical cyclone. The season concluded with Tropical Storm Rina, which became extratropical on November 9.
Tourists left coastal towns, emergency shelters were opened, and storm drains were cleared before the onset of heavy rainfall. At least 53 municipalities in Mexico were affected by Katia. Heavy rainfall left flooding and numerous mudslides, with 65 mudslides in the city of Xalapa alone. Preliminary reports indicated that 370 homes were flooded. Three deaths were confirmed to have been related to the hurricane, with two from mudslides in Xalapa and one from being swept away by floodwaters Jalcomulco. Approximately 77,000 people were left without power at the height of the storm. Agricultural losses alone reached about $2.85 million, while infrastructural damage totaled about $407,000. Coincidentally, the storm struck Mexico just days after a major earthquake struck the country, worsening the aftermath and recovery.
In terms of sustained winds, Irma, at the time, became the strongest hurricane ever recorded in the Atlantic basin outside of the Gulf of Mexico and Caribbean, with maximum sustained winds of 180 mph (285 km/h); it was later surpassed in 2019 by Hurricane Dorian.