At a Glance
- Sometimes, storms can form before the June 1 official season start.
- From 2015-23, at least one storm formed before June 1 in all but one of those years.
- This isn't out of the question again in 2024, especially given record warm ocean water.
- Such preseason activity doesn't forecast the outcome of the hurricane season.
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Atlantic hurricane season officially kicks off in June, but it has jumped the gun with at least one storm in most years since the mid-2010s, and that could happen again in 2024.
The recent "preseason" stretch: From 2015 through 2023, at least one named storm formed in the Atlantic Basin prior to June in each of those years except 2022. You can see their tracks plotted on the map below.
One year ago, the National Hurricane Center announced their post-analysis revealed a January subtropical storm formed off the U.S. East Coast. So, technically, that was the first of the 2023 hurricane season. But since it wasn't named at the time, the "A" name (Arlene) went to a Gulf tropical storm in early June that year.
Some were impactful: While some of these storms were short-lived and far from land, at least 20 deaths and about $200 million in damage can be attributed to May storms from 2012 through 2020, according to the World Meteorological Organization.
In 2016, Tropical Storm Bonnie soaked the coast of the Carolinas in late May. That was preceded by eastern Atlantic Hurricane Alex, only the second known January Atlantic hurricane. Alex eventually made landfall in the Azores as a tropical storm.
In 2012, Tropical Storm Beryl almost reached hurricane strength before landfall on Memorial Day weekend in northeast Florida.
This season: In general, one ingredient tropical cyclones need to develop is water of around 80 degrees. That's already in place in the Caribbean Sea, the Florida Straits and adjacent southwest Atlantic Ocean north of Cuba, Hispaniola, Puerto Rico and the Leeward Islands.
In fact, a strip of the tropical Atlantic from the Caribbean Sea to Africa is as warm as usual for late June, according to University of Miami tropical scientist Brian McNoldy.
Given that record-warm water for this time of year, if there's a lack of shearing winds and dry air, we can't rule out yet another preseason storm in 2024.
Why it "starts" June 1: Officially, the Atlantic hurricane season runs from June 1 through Nov. 30. That time frame encompasses over 97% of all Atlantic tropical storms and hurricanes, according to NOAA's Hurricane Research Division.
In 1935, the season was set from June 15 through Nov. 15 to match up with a special telegraph line connecting the various centers of the U.S. Weather Bureau, according to NOAA-HRD. In 1964 and 1965, those start and end dates were adjusted to June 1 through Nov. 30. They've been the same ever since.
What NHC does now: No changes have yet been made to the official start or end dates of hurricane season.
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"In 2021, the National Weather Service assembled a team to determine quantitative thresholds for adding or removing dates from the official Atlantic hurricane season, along with an examination of the potential ramifications of moving the beginning of hurricane season to May 15," said Maria Torres, a meteorologist and communications and public affairs office at the National Hurricane Center, in an email to weather.com.
Torres said the team found moving the start date two weeks earlier would add only 1% of activity. She also noted the rarity of May storms to become hurricanes, the last of which occurred in 1970 (Hurricane Alma).
Based on those findings, the World Meteorological Organization's Hurricane Committee – which ultimately makes decisions on definitions of hurricane seasons – is not pursuing any changes to the hurricane season's official dates.
However, beginning in 2021, the National Hurricane Center moved up the date at which they begin issuing their Atlantic tropical weather outlooks to May 15 to cover these potential preseason storms. These outlooks issued four times each day show areas where tropical development is possible over the next seven days.
Early storm can't predict entire season: We examined all hurricane seasons in the satellite era – from 1966 through 2023 – parsing out whether or not they produced at least one storm before June 1.
As you might expect, the 18 seasons with at least one pre-June 1 named storm ended up with an average of three to four more storms for the season than the 39 seasons without a preseason storm.
However, the number of hurricanes and major hurricanes (Category 3 or stronger) were virtually the same in seasons that started early compared to those that did not. This is because the overwhelming majority of both hurricanes and major hurricanes occur in the peak months of August through October.
So there's little useful information we can take away from the presence or lack of a pre-June 1 storm for the hurricane season.
Now is a good time to develop or refresh your hurricane plan well before the season's first hurricane.
MORE ON WEATHER.COM
- 2024 Hurricane Season Outlook
- How This Outlook Compares To Busiest Seasons On Record
- When Was The Last 'Quiet' Hurricane Season?
Jonathan Erdman is a senior meteorologist at weather.com and has been covering national and international weather since 1996. His lifelong love of meteorology began with a close encounter with a tornado as a child in Wisconsin. He completed a Bachelor's degree in physics at the University of Wisconsin-Madison, then a Master's degree working with dual-polarization radar and lightning data at Colorado State University. Extreme and bizarre weather are his favorite topics. Reach out to him on X (formerly Twitter), Threads, Facebook and Bluesky.
