Puerto Rico is situated at the northeastern boundary of the Caribbean Sea, placing it directly in the path of tropical cyclones that form in the Atlantic Basin and track westward. This geographical positioning means the island is regularly exposed to the annual Atlantic hurricane season, which officially runs from June 1st to November 30th. The island’s history is marked by the significant impacts of these weather events, making the frequency of storms a major public concern.
Statistical Frequency of Hurricane Strikes
Puerto Rico is affected by tropical weather yearly, though not always by a direct hurricane strike. On average, the island region is exposed to a tropical storm or hurricane event approximately four times each season. This exposure includes storms that pass close enough to generate tropical-storm-force winds (39 to 73 miles per hour).
When looking specifically at direct hurricane landfalls, which occur when the eye of the storm crosses the coastline, the frequency drops significantly. The average return period for a hurricane to make landfall is estimated to be around once every five to ten years. This calculation accounts for any storm reaching hurricane status (74 miles per hour or greater). Between 1851 and 2019, Puerto Rico experienced a total of 32 direct cyclone landfalls, a figure that includes both tropical storms and hurricanes.
The Difference Between a Hit and a Major Strike
Not all hurricanes pose the same level of risk, requiring differentiation between a “hit” and a “major strike.” The Saffir-Simpson Hurricane Wind Scale classifies hurricanes into five categories based on wind speed. Category 3, 4, and 5 storms are considered “major hurricanes,” sustaining winds of 111 miles per hour or greater and capable of causing catastrophic damage.
The probability of a major hurricane striking Puerto Rico is much lower than the probability of any hurricane. Historical data indicates that the return period for a major hurricane (Category 3 or higher) making direct landfall is approximately once every 10 to 15 years. Between 1851 and 2019, only nine of the 32 total cyclone landfalls were classified as major hurricanes upon impact.
Historical Impact of Devastating Storms
While major strikes are less frequent, their consequences have profoundly shaped the island’s infrastructure and history. The 2017 season provided a modern example when Hurricane Maria made landfall as a powerful Category 4 storm.
Maria’s impact on September 20, 2017, was catastrophic, crippling the island’s electrical grid and causing an estimated $90 billion in damage. This storm was the strongest to strike the island in nearly a century, bringing heavy rainfall, a large storm surge, and high winds. Its destruction was compounded by the fact that Hurricane Irma, a Category 5 storm, had passed just northeast of Puerto Rico only two weeks earlier.
Earlier storms also illustrate this risk, notably the San Felipe Segundo hurricane of 1928, which was the strongest storm on record to strike the island, making landfall as a Category 5. Hurricane Hugo in 1989 also struck the island as a Category 3 storm, causing widespread damage before proceeding north. The island’s exposure can fluctuate dramatically from one season to the next, regardless of the long-term averages.