Hurricane Janet was the most powerful tropical cyclone of the 1955 Atlantic hurricane season and one of the strongest Atlantic hurricanes on record. Janet was also the first named storm to cause 1,000 deaths and the first Category 5 storm name to be retired. The eleventh tropical storm, ninth hurricane, and fourth major hurricane of the year, Janet formed from a tropical wave east of the Lesser Antilles on September 21. Moving westward across the Caribbean Sea, Janet fluctuated in intensity, but generally strengthened before reaching its peak intensity as a Category 5 hurricane with winds of 175 mph (282 km/h). The intense hurricane later made landfall at that intensity near Chetumal, Mexico on September 28. 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. Janet quickly weakened over Mexico's mountainous terrain before dissipating on September 30.

The 1955 Atlantic hurricane season was, at the time, the costliest season ever recorded, just ahead of the previous year. The hurricane season officially began on June 15, 1955, and ended on November 15, 1955. It was an extremely active season in terms of accumulated cyclone energy (ACE), but only slightly above average in terms of storm formation, with 13 recorded tropical cyclones.