JACKSONVILLE, Fla. — Ahead of the Atlantic hurricane season beginning June 1, the National Hurricane Center has already started issuing daily tropical weather outlooks, which began Thursday.

That might raise eyebrows, but history shows tropical systems don’t always wait for the calendar to flip to June.

Since official records began in 1851, a total of 32 named tropical and subtropical storms have developed in the Atlantic Ocean during the month of May. Of those, four storms strengthened into hurricanes — rare, but not unprecedented.

• Unnamed hurricane – May 1889

• Unnamed hurricane – May 1908

• Hurricane Able – May 1951 (the first named May hurricane)

• Hurricane Alma – May 1970

Most May storms tend to form in the Gulf of America or the western Atlantic, where sea surface temperatures warm earlier in the year. These regions are more conducive to early-season development compared with the open tropical Atlantic, which generally stays too cool for storm formation until later in the summer.

Despite recent years bringing more preseason activity, May hurricanes remain uncommon. The primary reasons are lower ocean temperatures across much of the basin and stronger wind shear, both of which make it difficult for tropical cyclones to organize and intensify.

Still, the NHC’s decision to begin monitoring mid-May is based on data — not the calendar. Conditions can change quickly, especially in the western Caribbean and Gulf. In fact, there was talk on starting the hurricane season in Mid-May several years ago, but it was settled to just start putting out warnings in mid-May.

For more information on the tropical outlook and hurricane preparedness tips, click here.