Hurricane Milton joins the rare list of Category 5 storms in the Atlantic basin

Hurricane Milton added its name to the rare list of Category 5 hurricanes in the Atlantic basin on Monday, joining Beryl earlier this season.

Category 5 hurricanes occupy the highest status in the Atlantic basin. A hundred years of history have shown that there are favorite places and seasons, but there are also outliers, especially in recent years.

Milton and Beryl are the newest members: According to Dr. According to Phil Klotzbach, a tropical scientist, Milton was upgraded to Category 5 at 11:55 a.m. EDT on Monday, making it just the second Gulf of Mexico hurricane to reach that intensity in October, joining 2018's Michael, since satellite detection began of storms in 1966 at Colorado State University.

Earlier this season, Beryl became the record-breaking Category 5 hurricane in an Atlantic hurricane season on the evening of July 1, 2024. Beryl surpassed 2005's Hurricane Emily – the earliest Category 5.5 hurricane to date – by a whopping 15 days. This was just one of the many records Beryl broke earlier in the season.

Category 5 is the highest classification a hurricane can achieve: For a hurricane to reach this strength, maximum sustained wind speeds of 157 miles per hour or more are required on the Saffir-Simpson hurricane wind scale. If you are more familiar with the EF scale for tornadoes, this corresponds to the estimated wind strengths of an EF3 tornado or stronger.

Before Milton and Beryl, there were only 40 such Category 5 hurricanes in the Atlantic basin since 1924, according to NOAA's historical database.

It's even rarer for two Category 5 storms to occur in the same season: Only five other seasons in the Atlantic basin have produced two or more Category 5 hurricanes since 1950, Klotzbach said in a post on X.

The last year was 2019 when Dorian and Lorenzo reached this strength. 2005 had the most with four, including Emily, Katrina, Rita and Wilma.

There have been ten Category 5 hurricanes in the Atlantic since 2016: In addition to Beryl and Milton, this recent spate of Category 5 Atlantic hurricanes includes Lee in 2023, Ian in 2022, Dorian and Lorenzo in 2019, Michael in 2018, Maria and Irma in 2017, and Matthew in 2016.

The four-year streak from 2016 to 2019 with at least one Category 5 hurricane was the longest on record.

There were also long “droughts”: Before Matthew in 2016, there were eight consecutive non-Category 5 hurricane seasons in the Atlantic. Hurricanes Allen and Gilbert were separated by another eight years, from 1980 to 1988.

They most commonly occur at the height of hurricane season: Category 5 hurricanes were by far the most common in September. But they also happened at least half a dozen times each in August and October.

This includes the most active period of the hurricane season. This is because all the favorable conditions and ingredients for development most likely overlap in a large area of ​​the Atlantic basin.

They formed most frequently here in the Atlantic: The map below shows in red segments the locations where hurricanes have reached Category 5 intensity, including Hurricane Beryl earlier this season.

Aside from the oddity caused by Hurricane Lorenzo in the Far Eastern Atlantic in 2019, you will notice that almost all of them occur in the same area, from the Southwest Atlantic north of the Lesser Antilles to the Caribbean and the Gulf of Mexico.

These areas are so conducive to strengthening because they have deep, warm seawater, there are no hostile wind shear during hurricane season, and they have a number of disturbances known as tropical waves that serve as seeds for development. The supply of deep, warm seawater that fuels hurricanes is highest in the Atlantic basin in these areas, particularly in the Caribbean Sea.

Hurricanes do not maintain Category 5 intensity for long: On average, a hurricane maintains Category 5 status for just under 24 hours.

That's because strong hurricanes typically go through one or more eyewall replacement cycles. During one of these events, the hurricane's intense ring of thunderstorms around its eye is surrounded by a new outer ring.

In this case, the hurricane's wind intensity temporarily decreases as the former eyewall becomes clogged. Usually it strengthens again as the new outer eyewall is pulled inward, resulting in a larger hurricane.

Several Category 5 hurricanes reached this intensity several times during their lifetime.

Hurricanes Allen (1980), Isabel (2003) and Ivan (2004) each reached Category 5 intensity three times during their journeys.

The November 1932 Cuba hurricane (78 hours) and 2007 Hurricane Irma (77 hours) combined spent the longest time at Category 5 strength, according to the NOAA database.

Only four recorded hurricanes have made landfall on the U.S. mainland at Category 5 intensity: The most recent of these was Hurricane Michael in the Florida Panhandle in October 2018.

Others include Andrew in 1992 in South Florida, Camille in 1969 on the Mississippi Gulf Coast, and the 1935 Labor Day hurricane in the Florida Keys.

Hurricane Ian nearly did that in 2022, but became a still-strong Category 4 hurricane when it made landfall.

Chris Dolce has been a senior meteorologist at Weather.com for over 10 years, having started his career at The Weather Channel in the early 2000s.

Jonathan Erdman is the senior meteorologist at Weather.com and has been an incurable weather nerd since a tornado narrowly missed his childhood home in Wisconsin when he was 7 years old. Contact him at X (formerly Twitter), Facebook and threads.