After weakening over the Yucatán Peninsula, it moved into the Bay of Campeche, where it slightly strengthened before making its final landfall near Veracruz on September 29.

At Janet's second landfall near Veracruz, significant river flooding ensued, worsening effects caused by Hurricanes Gladys and Hilda earlier in the month.

Although it was speculated that the disturbance originated from a tropical wave near Cape Verde, the Weather Bureau considered the system too weak to be detected due to a lack of reports from the islands.

After passing between the islands of Grenada and Carriacou in the morning hours of September 23, Janet entered an area of unfavorable conditions in the eastern Caribbean Sea.

[4][3] A U.S. Navy reconnaissance plane entered the hurricane early on September 24, reporting a lack of organization, and noting an indiscernible center of circulation with weak rainbands.

[6][4] While trekking across the central Caribbean Sea, Janet was only slightly larger than while it was moving over the Windward Islands, with gale-force winds extending 125 miles (201 km) out from the center by September 25.

[6] Remaining a Category 4 hurricane as it moved erratically westward across the Caribbean, a reconnaissance flight mission during the night of September 25–26 indicated strong rainbands with frequent lightning strikes and a well-defined eye, evidence that the storm was once again rapidly intensifying.

In that city, an anemometer at the airport reported winds of 175 mph (282 km/h) before being blown away, and a barometer indicated a minimum barometric pressure of 914 mbar (27.0 inHg) in the eye of Janet.

[4][6] The weakened hurricane marginally intensified as it crossed the Bay of Campeche to a secondary peak intensity of 110 mph (180 km/h) with a minimum central pressure of 950 mbar (28 inHg).

[4] Janet eventually made its final landfall 50 miles (80 km) north of the city of Veracruz by 2200 UTC on September 29 as a Category 2 hurricane.

After moving inland, the hurricane became quickly disorganized due to the highly mountainous terrain of Mexico, and as a result the Weather Bureau issued its last advisory on Janet.

[6] Upon Janet's formation east of the Windward Islands, the Weather Bureau office in San Juan, Puerto Rico advised small craft to remain in port and vessels in the path of the developing storm to exercise caution.

After a reconnaissance flight reported much stronger winds than initially suggested, hurricane warnings were issued at 1600 UTC on September 22 for the entirety of the Lesser Antilles from Saint Lucia to Grenada, including Barbados.

Though no official warnings were issued for areas of Central America, advisories published by the Weather Bureau cautioned interests in the hurricane's path up until landfall.

[9] After the hurricane moved through the Yucatán Peninsula and entered the Bay of Campeche, the Weather Bureau alerted areas in the storm's path on the western side of Mexico's Gulf Coast.

[29] The exact cause of the crash remains unknown, though it is speculated that the plane's altimeter gave an incorrect reading due to the low surrounding barometric pressure[30] or that the excess workload placed on one of the crew members due to another crew member having been replaced by one of the reporters caused him to lose track of the plane's height above the water.

[33] After passing the Swan Islands, Janet made landfall on the Yucatán Peninsula between Corozal Town, British Honduras, and Chetumal, Mexico, at 1700 UTC on September 28.

[34] In Xcalak, Quintana Roo the strong winds from Janet flattened the port's infrastructure, and only one house remained intact after the storm's passage.

[3] Making landfall near the border between Mexico and British Honduras, the latter colony's Corozal and Orange Walk districts, containing a population of 15,500 at the time, experienced severe devastation from Janet.

[42] In British Honduras, the hurricane's effects were less deadly than in Quintana Roo,[43] but in northern portions of the colony the storm killed 16 people and caused $5 million in damages.

[3] While in the Bay of Campeche, the shrimp boat Celestino Arias was sunken by strong waves generated by Janet after it suffered engine failures.

[48] The floods contributed to a localized typhoid fever and dysentery outbreak,[49][50] causing over 1,000 people to evacuate out of the city to prevent further spreading of the diseases.

[50] Although located south of where Janet made landfall, areas of Veracruz were inundated by strong storm surge, including the city's main streets and port.

[51] Farther inland, as Janet dissipated over the mountainous central Mexico, the storm dropped torrential rainfall over the Tamesí and Pánuco River basins.

[56] Combined property damage in Mexico from Hurricanes Gladys, Hilda, and Janet was estimated to total $200 million, nearly half of the government's 1955 national budget.

[16] Relief workers on Barbados helped to clean up debris scattered by the strong winds on highways, and the local government made requests for food and construction materials.

The NHA was responsible for the acquisition of lands on which houses could be built with stronger and more permanent materials, which was thought to minimize maintenance costs and hurricane-related damage.

[nb 3][63] The Crown Agents and Red Cross delivered relief supplies to Barbados and the Grenadines, which included aluminum roofing sheets and portable electric generators.

[65] The government also declared a state of emergency for Corozal, Orange Walk, and Belize administrative districts, including a ban on liquor sales.

[38] However, after crossing the Bay of Campeche and making landfall near Veracruz, relief measures were once again implemented in the western Gulf Coast of Mexico.