The recent increase in Atlantic hurricane activity has not increased the threat to the United States. In fact, there has been a significant decline in hurricane numbers over Florida since the middle 20th century. Florida's decline results from fewer hurricanes passing through the Bahamas and the western Caribbean Sea. Here we show a trend in surface-air temperatures, consistent with global warming, that inhibits deep convection over the Greater Antilles and adjacent waters during the hurricane season leading to tropospheric flow patterns increasingly unfavorable for tropical cyclogenesis throughout the northern Caribbean region. Improving risk assessment of future powerful hurricane strikes in this highly developed coastal region has the potential for reducing societal vulnerability through greater preparedness and insurance mechanisms.