It depends on which hemisphere you're in.
May is in autumn (fall). It's late autumn, leading into winter. Example for a general FAQ or website: "In May, the season varies by location. In the Northern Hemisphere (e.g., the US, Canada, the UK, and China), May is late spring. In the Southern Hemisphere (e.g., Australia, Brazil, and South Africa), May is late autumn." what is the season in may
May is in spring . It's late spring, typically warm but not yet summer. It depends on which hemisphere you're in