After entering the Caribbean, Inez briefly weakened before restrengthening, attaining peak sustained winds of 165 mph (270 km/h) on September 28, eventually making landfall at that intensity in the Dominican Republic.

Damage totaled $20.35 million in Haiti, prompting the United States government to send aid for the first time in nearly ten years due to previous mishandling of funds.

The hurricane threatened the northern Yucatán Peninsula, and although it remained offshore, Inez produced flooding and caused some power outages.

Tracked by satellites, the system moved to the west-southwest,[3] and was officially classified a tropical depression on September 21 about halfway between the Lesser Antilles and Africa.

[2] Inez slowed while curving westward around a ridge to its north and quickly intensified,[3] reaching hurricane status on September 26.

However, Inez re-intensified after entering the eastern Caribbean Sea, reaching a minimum pressure of 927 mbar (27.4 inHg) south of Puerto Rico on September 28.

[4] In 2017, a preliminary re-analysis conducted as part of the ongoing Atlantic hurricane reanalysis project raised Inez's peak intensity from its original 150 mph (240 km/h).

While near peak intensity, Inez was located about 160 mi (260 km) southwest of San Juan, Puerto Rico, and the eye was tracked by radar from the island.

However, Inez quickly re-intensified over water, reaching winds of 115 mph (185 km/h) on September 30 before striking southeastern Cuba near Guantánamo Bay.

The hurricane drifted west-northwestward within light steering currents, weakening over the high terrain but later moving offshore the southern coast of Cuba.

[3] Shortly after exiting Cuba into the Atlantic, Inez weakened into a tropical storm, and was moving northeastward through the Bahamas about 24 hours later than forecast.

[3] The unusual track of Inez marked the first time on record that a tropical cyclone affected the Lesser and Greater Antilles, Bahamas, Florida, and Mexico.

"[6] It was also the first to move across the Gulf of Mexico without turning to the north so late in the season, and the 65 advisories issued by the NHC was the highest number at the time.

[8] When Inez was near peak intensity, the NHC warned residents in southern Haiti and the Dominican Republic of the danger posed by the hurricane.

[14] In the northern Gulf of Mexico, a helicopter crashed after evacuating workers from an oil platform about 65 mi (105 km) south-southwest of Morgan City, Louisiana, in otherwise calm conditions; 11 people died, including the pilot.

When Inez passed south of Puerto Rico, its rainbands produced gusty winds along the island's southern coast, reaching 50 mph (80 km/h) in Peñuelas.

In the capital city of Santo Domingo, heavy rains flooded hundreds of homes along the Ozama River, forcing thousands to evacuate.

High rainfall led to flash flooding between mountain ranges,[22] in a location nicknamed the "valley of death"; there, the Weather Bureau remarked that "local winds... may well have exceeded 160 mph (260 km/h)".

The United States government reported that the hurricane "killed no more than 50" in Haiti, and "nor was there a real emergency," due to president François Duvalier misusing previous aid.

[24] The U.S. assessment was incorrect, as the 1966 annual tropical cyclone summary in the Monthly Weather Review indicated 750 deaths in Haiti,[3] mostly in Jacmel.

[23] A station at Guantánamo Bay reported winds of 138 mph (222 km/h) when Inez moved ashore in Cuba, and rainfall reached 12 in (300 mm).

[3] In the Straits of Florida, high waves from Inez overturned a 24 ft (7.3 m) blockade runner carrying Cuban exiles to Miami.

[28] Inez was considered a "dry hurricane", and about 1 in (25 mm) of the precipitation that fell was largely in the form of sea water spray.

[29] Light rainfall occurred in Miami, where strong winds damaged crops due to salt spray onto local vegetation.

Winds and salt spray severely damaged vegetables in southern Dade County, including up to 80% losses of tomatoes in some farms.

[26] Statewide, damage totaled $5 million,[3] and there were four deaths; three were elderly people who died of heart attacks while installing shutters, and the fourth was a teenager who was swept by large surf.

[32] When Inez was making its final landfall in Mexico, its outer circulation reached southern Texas, producing winds of 22 mph (35 km/h) and trace rainfall.

[3] In northeastern Mexico, more than 3,000 people were stranded by flooding after dozens of rivers and streams rose above their banks, forcing some families to hold onto trees.

[19] Due to the heavy damage in Hispaniola, VMM-365, a United States Marine Corps helicopter division, spent 454 hours and flew 740 sorties to provide 186,676 tons of relief supplies to Haiti and the Dominican Republic.

[46] The country's military sent helicopters and planes to join the Mexican Air Force,[37] as well as trucks by land,[18] to deliver tons of supplies, including food, clothing, and medicine to flood-affected areas in Tamaulipas.