The hurricane season stretches from June 1st to November 30th. However, in recent years there have been named storms forming in April, May, and even January. 2015, 2016, 2017, 2018, 2019, 2020, 2021, and 2023 all had named storms form before the official start of the hurricane season.

This market resolves YES if a tropical or subtropical storm forms before June 1st in the local time in the location where it forms. A storm in the part of the Atlantic in the southern hemisphere would count, but tropical activity there is exceedingly rare.

See also my El Nino / La Nina market for hurricane season: https://manifold.markets/SaviorofPlant/will-it-be-el-nino-la-nina-or-neith. El Niño tends to suppress Atlantic tropical cyclone activity, while La Niña tends to enhance it.