On my Macbook Pro running Mac OS X 10.8.2 (Mountain Lion) all the birthdays from the "Birthdays" calendar are showing a day early in Calendar. E.g. When I browse to contact Joe Bloggs in Contacts it shows his birthday as 12/03/1987. When I go into Calendar, there is a full day event for Joe Bloggs' birthday on 11/03/1987.

In Calendar I have selected the correct timezone (New Zealand Time) and have also enabled "Turn on time zone support" in the preferences. On my iPhone, I have the same settings and the birthdays display on the correct date.

Is there anything I can do to get the birthdays to display on the correct date in Calendar on my Macbook Pro?

Edit: Just clarifying, the date format used here is dd/mm/yyyy.

  • Just out or curiousity, have you tried changing the date format in Contacts to mm/dd/yyyy? Maybe it's possible Calendar doesn't get the format. Just a quick, early morning thought.
    – Richard
    Commented Nov 23, 2012 at 11:29
  • This sould like you have scheduled a default reminder a day earlier. Have you checked the reminders (should be visible in the details of calendar entries).
    – cyphorious
    Commented Nov 23, 2012 at 12:47
  • @Richard Still a day early, it understands the format just fine. All my other events are on the correct days. Commented Nov 23, 2012 at 19:04
  • @cyphorious Nope. It clearly puts the birthday event itself on the day before, not just a reminder. Commented Nov 23, 2012 at 19:05

3 Answers 3


I was having a similar issue for a while using the native Birthday calendar. It's not exactly the same as only the notifications came in one day early.

To fix this, in macOS El Capitan with Calendar v8.0 (2092.3), I found the following:

  1. Open the Calendar app on macOS
  2. Select Preferences > Alerts
  3. Here change the notification for Birthdays to your choice (in my case "On day of event")

I looked for this option a while ago but was unable to find it earlier. But now with this, I'm neatly notified on the day of a birthday. Perhaps it helps others as well.

Screenshot Calendar


I also have this problem ( also in NZ) but it seems to only be birthdays in November and December and January which are wrong. Weird.

Perhaps if anyone with NZ localization sees this on the three month window (11/12/1) it's actually a bug in the code and not something we are doing incorrectly with our data when entering it.

  • I've added some conjecture since your discovery that it's only three months might move someone to figure the root cause out (or at least document how this is failing in a limited set of data).
    – bmike
    Commented Jun 9, 2013 at 15:34

It's not just Nov/Dec/Jan. I'm in NZ too and my friend's birthday in Feb is also wrong. Not impressed (nor are my friends!)

  • Actually it's worse than that. My contact cards are all incorrectly updated. So their contact cards are incorrect. They were entered years back correctly, but now they're incorrectly showing the day prior. For me it's inconsistent. This is the first place where I've found similar experiences and I know it's not consistently wrong, but I haven't got around to fully determining whether it's certain month specific only.
    – user69370
    Commented Feb 3, 2014 at 10:09

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