It also becomes the third hurricane to strike Florida as a Category 5, and its October landfall made it the latest a storm this strong has ever struck USA shores.
The post-storm analysis was done by compiling data from aircraft measurments, surface winds and pressure, as well as satellite and Doppler radar estimates. Now, scientists believe they underestimated Michael's wrath, reclassifying the wind speeds to be 5 miles per hour higher than initial calculations.
Michael was responsible for 16 deaths and caused about $25 billion in damage to the U.S. Cuba also was hit by Category 2 winds from Michael. The last hurricane of such intensity at landfall was Hurricane Andrew, which struck South Florida and Louisiana in 1992.
According to NOAA, Category 5 winds were likely experienced over a small area, and the change is of little practical significance.
"You still ride through our city and it's depressing", Cathey said, adding that they've dealt with 1 million cubic yards (0.76 million cubic meters) of debris.
Aerial footage after the storm showed massive damage and destruction in coastal cities in the Panhandle, such as Mexico Beach and Panama City Beach.
Just 36 hours before hitting Florida's coast, Michael was making its way through the Gulf of Mexico as a 90 mph (145 kph) Category 1 storm. The others were the Labor Day Hurricane in 1935 and Hurricane Camille in 1969. Vacant lots line USA 98 as it winds west toward Panama City, also heavily damaged by the storm.
The upgrade comes after the National Hurricane Center sifted through and reanalyzed reams of data. Another 43 deaths in Florida were associated indirectly with Michael: falls during cleanup after the storm, medical issues made worse by it, and traffic accidents.
The estimated damage totaled near $25 billion, according to the report, with almost $18.4 billion from Florida alone.