How to pronounce “may 31” in English

And on May 31, 1991, Olaf made a presentation that was not heavily attended because Sony was a small player at the time and said,

The first episode will be May 31.

For instance, May 31, 2015 was a day that changed my life forever.

So I was asked in May-- I think the premier is May 31, right?

And I said, Greg, if 10,000 people had showed up on Springfield on May 31, would the vote have happened?