Wrong Birthday with siri in macOS Sierra

Same problem here on a Dutch system, see: Siri's birthday one day off

It may a localization issue. I am in Portugal but my system is in English and I do NOT have the issue.

I will try in Portuguese (not at my mac right now) and will let you know.

I have the exact same issue as well, and I am using English (UK) language and localisation is set to UK. My iPhone and iPad report the correct birthday whilst MacOS reports all birthdays minus one day.

The stupid thing is - it pulls up a card with the contact information for the person you are asking for and the date shown in the correct day, but it speaks the wrong day.

Same issue here. I'm in Australia. This is just happening on my Macbook Pro, Siri on all my other iOS devices is fine.

I am facing similar issues. I have figured out that SIRI speaks correct birthdays only if you have selected a Western Time-zone (i.e any time zone west of Greenwich...Say for example New York or Brazil). I initially thought that it is happening since my time zone (which is New Delhi) is on a different date than American time zone (specifically US-Pacific time). But that is not the case. It doesn't matter whether local date is same as the US date. The only thing that matter is the Time-Zone. Try changing the time-zone to any Western Time zone and you will see that SIRI has started to speak correct birthdays. I think it is some kind of bug in OS. Trying to figure out. Hope to find an answer soon.

No, still same problem

Same here from UK, 1 day previous than actual date. iOS works fine, just seems to be on macOS Sierra.

I have the same issue on my iMac. Birthdays are one day off. Located in Belgium, using English (UK) MacOS Sierra 10.12.3.

This problem is solved with the last update from Sierra.

Thanks for notifying. I installed 10.12.4 this morning and indeed: problem solved!