Rarity of June hurricanes: Only 2 have formed east of Caribbean islands in history

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How rare is June tropical activity?

The National Hurricane Center is keeping its eye on Tropical Storm Bert, which formed in the central Atlantic Ocean on Monday. FOX Weather meteorologists Michael Estime and Kendall Smith break down how rare it is to see tropical activity this early in the season.

The 2023 Atlantic hurricane season began on June 1, and it has already gotten off to an active start with the development of Tropical Storm Arlene on June 2 and Tropical Storm Bert on Monday.

It’s rare for multiple disturbances to develop into tropical storms this early in the season, as the first named storm doesn't typically form until June 20, and the average first hurricane in the Atlantic isn't until Aug. 11.

‘Rather rare June event’

This map shows where tropical cyclone activity tends to occur during June. The data are shown as the combined number of tropical depressions, tropical storms and hurricanes whose centers pass within 125 miles of a point on the map during a 100-year period. The analysis is based on data from the 72-year period from 1950 to 2021 but normalized to 100 years.

(FOX Weather)

The month of June is usually not very active in the tropics, and any named storms that do form typically develop closer to the U.S. in the Gulf of Mexico, the western Caribbean Sea and near the Southeast and mid-Atlantic coasts.

Between 1851 and 2020, only 6% of all tropical storms and 2% of all hurricanes roamed the Atlantic during June, according to data from NOAA's Atlantic Oceanographic and Meteorological Laboratory.

Tropical Storm Bert moved off the coast of Africa last week, and that's not something typically seen in June.

"This is a rather rare June event," FOX Weather meteorologist Kendall Smith said. "We typically see systems kind of forming right off the coast of Africa tracking through what we call the MDR, the Main Development Region, typically in August. We are well ahead of schedule. That’s also why this is a big cause for concern."

Only 4 named storms formed east of the Lesser Antilles in June

According to records dating back to 1850, before Bert there had only been two tropical storms and two hurricanes that formed east of the Lesser Antilles in June.

One of those hurricanes was the 1933 Trinidad Hurricane, and the second was Hurricane Elsa in 2021. 

Earlier forecasts from the NHC on Monday had Bert perhaps strengthening into a hurricane by midweek and becoming the third such storm, but latest forecast data Tuesday morning indicates a more unfavorable environment for Bert and the storm was now expected to remain at tropical storm strength.