The 1924 Atlantic hurricane season featured the earliest known Category 5 hurricane – a tropical cyclone with maximum sustained winds exceeding . The first system, Tropical Storm One, was first detected in the northwestern Caribbean Sea on June 18. The final system, an unnumbered tropical depression, dissipated on November 24. These dates fall within the period with the most tropical cyclone activity in the Atlantic. Of the 13 tropical cyclones of the season, six existed simultaneously. The season was average with 11 tropical storms, five of which strengthened into hurricanes. Further, two of those five intensified into major hurricanes, which are Category 3 or higher on the Saffir–Simpson hurricane wind scale. The most significant storm of the season was Hurricane Ten, nicknamed the 1924 Cuba hurricane. It struck western Cuba as a Category 5 hurricane, before weakening and making landfall in Florida as a Category 1 hurricane. Severe damage and 90 fatalities were collectively reported at both locations. Another system, Hurricane Four, brought strong winds and flooding to the Leeward Islands. The storm left 59 deaths, 30 of which were on Montserrat alone. Several other tropical cyclones impacted land, including Tropical Storms One, Eight, and Ten, as well as Hurricanes Three and Five, and the remnants of Hurricane Three and Four. Overall, the storms of the 1924 Atlantic hurricane season collectively caused at least 179 fatalities. The season's activity was reflected with an accumulated cyclone energy (ACE) rating of 100, above the 1921–1930 average of 76.6. ACE is a metric used to express the energy used by a tropical cyclone during its lifetime. Therefore, a storm with a longer duration will have high values of ACE. It is only calculated at six-hour increments in which specific tropical and subtropical systems are either at or above sustained wind speeds of , which is the threshold for tropical storm intensity. Thus, tropical depressions are not included here. Timeline Systems Tropical Storm One A tropical storm was detected southeast of Chetumal, Quintana Roo on June 18. It made landfall on northern Belize with estimated winds near . Pressures were progressively decreasing over the preceding days in the northwestern Caribbean Sea. The tropical system crossed the Yucatán Peninsula, emerging over the Bay of Campeche on June 19 with winds. It re-strengthened over water and re-attained winds of . Early on June 21, the storm made landfall south of Tampico, Tamaulipas. It dissipated over land.