was one of only four Atlantic tropical cyclones on record to reach hurricane status in the month of December. Lili developed as a subtropical cyclone which originated from a frontal trough to the south of Bermuda on December 12. It tracked southeastward, then northward, slowly attaining tropical characteristics and becoming a hurricane on December 20. Lili turned to the south and southwest, briefly threatening the northern Caribbean islands before weakening and dissipating near the coast of the Dominican Republic. Lili was the longest lasting tropical cyclone outside of the Atlantic hurricane season, as well as the strongest hurricane to form during the month of December. It briefly threatened to pass through the Leeward Islands as a minimal hurricane, though upon passing through the area as a dissipating tropical depression Lili produced light rainfall and no reported damage. Storm names The following names were used for named storms that formed in the north Atlantic in 1984. No names were retired, so the same list of names was used again in the 1990 season. This is the first time these names were used since the post-1978 naming change, except for Bertha and Fran which were previously used in 1957 and 1973. Names that were not assigned are marked in . Season effects This is a table of the storms in 1984 and their landfall(s), if any. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but are still storm-related. Damage and deaths include totals while the storm was extratropical or a wave or low. |- | One || || bgcolor=#| || || || Florida || || || |- | Two || || bgcolor=#| || || || northern Mexico || || || |- | Three || || bgcolor=#| || || || None || || || |- | Unnumbered || || bgcolor=#| || || Unknown || None || || || |- | One || || bgcolor=#| || || || None || || || |- | Arthur || || bgcolor=#| || || || None || || || |- | Bertha || || bgcolor=#| || || || None || || || |- | Cesar || || bgcolor=#| || || || None || || || |- | Seven || || bgcolor=#| || || Unknown || northern Mexico || || || |- | Diana || || bgcolor=#|Category 4 hurricane || || || Southeastern United States || || 0 (3)