Don't get caught out: Setsubun is on the 2nd this year

I was sitting in the dentist's reception area today and they had the TV on in the background. Its muted, but they had the teletext on to show the subtitles. I wasn't in the humor to mess around on my phone so I was reading the subtitles to test my kanji proficiency! Thanks to that I realized that this year, just like 2021, Setsubun doesn't fall on February 3rd.

Setsubun most often falls on February 3rd. For more than one hundred years in a row it was celebrated on February 3rd. But in 2021 it fell on February 2nd. And this year, once again, it falls on February 2nd. Moreover, from here on in, for the next thirty years or so, it will fall on February 2nd almost every four years. 

Had it not been for report on the TV today, I may not have known it was going to be a day early this year. I was wondering though, why all the temples and shrines in my area are having their Setsubun festivals / Mamemaki ceremonies on the 2nd. I thought maybe they were opting to celebrate on a weekend, even though normally they celebrate on the day of Setsubun, even if it is a weekday.  But I was wrong: its because Setsubun falls on Sunday the 2nd of February 2025.