This only happened a few years ago.
I'm a midwestern emigree, I don't have major connections to California agriculture and I'm not latino, so the date isn't ingrained on my psyche. I always remember that Chavez's birthday is a holiday, but I always forget when it is until the day before.
Chavez's birthday is March 31.
I've got a day off work that I forgot about. I knew it was coming up at the end of the month, but when the end of the month came around, I forgot.