1851 Atlantic hurricane season

The 1851 Atlantic hurricane season was the first Atlantic hurricane season to be included in the official Atlantic tropical cyclone record. Six known tropical cyclones occurred during the season, three of which intensified into a hurricane, while one of those became a major hurricane. The earliest known storm formed by June 25 and the latest of which dissipated by October 19. Another storm was believed to have existed on September 18, but has since been removed from the official hurricane database (HURDAT). These dates fall within the range of most Atlantic tropical cyclone activity. None of the cyclones existed simultaneously with another, while three of the storms only have a single point in their track known.

The strongest and most intense cyclone, the fourth storm, peaked as a Category 3 hurricane on the present-day Saffir–Simpson scale with maximum sustained winds of 115 mph (185 km/h). Striking the Leeward Islands, Hispaniola, Cuba, and Florida at hurricane intensity in the second half of August, the system caused at least 23 deaths throughout its path. Tallahassee, Florida, alone reported about $60,000 (1851 USD) in damage. Another cyclone, the first storm, indirectly killed one person and caused some wind damage in Texas.

Two other hurricanes were reported during the season, one near Tampico and the other near Jamaica; however, they are not in the official hurricane database. There may have been other unconfirmed tropical cyclones during the season. Meteorologist Christopher Landsea estimates that between zero and six storms were missed from the official database, due to small tropical cyclone size, sparse ship reports, and relatively unpopulated coastlines. A 2014 study by climate researcher Michael Chenoweth theorizes that a total of 11 cyclones developed in the Atlantic in 1851, proposing the removal of the third and sixth storms but also the addition of seven undocumented systems. However, these changes have yet to be incorporated into HURDAT.