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How To Miss Your Flight (And Other Important Life Events) Courtesy of iCal

February 20, 2009
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Last week, I almost missed a flight due to iCal’s handling of time zones. And I’m going to show you how you can miss your very own flights – as well as other important life events – for free! You don’t even need to do anything special to miss your important appointments. All you have to do is use iCal as your calendar program (on Mac OS 10.4 Tiger or Mac OS 10.5 Leopard) and then travel to a different time zone.

Go ahead and try this simple experiment on your computer right now: Let’s say, for example, that you’re living in California. In your Date & Time system preference, click on the Time Zone tab and make sure that your Time Zone is set to PST, which can be accomplished by choosing any city in California, such as San Francisco.

Now let’s say that you’re traveling to New York this weekend and you have a lunch appointment scheduled for noon on Saturday in New York. Go ahead and add an appointment to your iCal calendar for noon this Saturday. So far, so good.

Okay, now let’s pretend that you’ve landed in New York and you want to change your system clock to match the time zone where you are currently traveling. Naturally, you will go back into your Date & Time system preference, click on the Time Zone tab, and change your Time Zone to EST by choosing New York for your city.

Go ahead and do that now, then take a look at your iCal calendar in horror.

Your lunch appointment has now shifted to 3:00pm. Your lunch appointment, which was actually supposed to take place at noon, is now supposedly taking place at 3:00pm. And, lo and behold, every other appointment on your entire calendar – past, present, and future — has shifted 3 hours later because you switched time zones.

Most business people live and die by their calendars being accurate, so the times that we enter should never change without our permission. If we can’t trust our very own calendar, what can we trust? And why is this happening?

iCal has a feature called “time zone support”, which you can turn on in iCal>Preferences>Advanced. Turning on this feature is what causes this behavior to happen, but the real problem here is that iCal does not stop this behavior when you turn this feature off. iCal always acts exactly the same, whether time zone support is turned on or off. As far as I’m concerned, the automatic adjusting of appointments should stop if you’ve never turned on time zone support to begin with, by making all of your appointments have a “floating time zone”. A “floating time zone” is assigned to an event whose time should always stays the same across all time zones. More on floating time zones in a moment, but first let me explain what happens when you turn on time zone support.

When you turn on time zone support, iCal will tag all of your appointments with a PST Time Zone (when you are creating them in the PST time zone), and then when you switch to a different time zone, iCal adjusts all of your appointments based on their former relationship to your new time zone. I think I am being conservative here when I say that 98% of all people using iCal do not want their appointments to auto-adjust appointment times for them. If you’re scheduling a lunch for yourself at noon, you‘re already thinking ahead to whatever time zone you’re going to be in, and so you put it on your schedule at noon. Likewise, if you’re scheduling a flight for yourself in the future, you’re typing it on your calendar for the local time zone in which you are going to be departing from (which is also how it appears on your airplane ticket), not adjusting its time for the time zone that you’re currently scheduling the appointment in. Imagine how you’ll feel when you show up to the airport 3 hours late for your flight that has already taken off without you!


When you turn on time zone support in iCal, you can assign a time zone to every appointment. The “Floating” time zone is the only choice that prevents your appointments from shifting times on your calendar, but there’s no way to make your appointments default to this selection.

I can understand that some people (my guess is less than 2%) might have a conference call back with the Los Angeles office while they’re traveling to Europe, and they want their calendar to automatically adjust for the time difference so they know when to call Los Angeles. Or maybe they want to keep track of when their favorite sports team is playing, so they want the game time to automatically adjust for them as they travel through time zones.

Great! If you’re one of those 2% of people who actually need this feature and are going to diligently use it, then that’s what time zone support was created for! All you need to do is turn on time zone support in iCal’s preferences, and then whenever you create a new appointment in iCal, you will notice that there is a new pop-up menu to choose from where you can associate a time zone with your appointment. Note that you will have to manually choose the appropriate time zone for every one of your appointments. Then, while you’re traveling, in the upper right-hand corner of iCal, there is a global pop-up menu that lets you choose which time zone your entire calendar is currently based in. As long as you have manually edited all of your appointments with the appropriate time zone, you will have an accurate calendar. But if you did not manually choose the right time zone for even a single appointment (or if you forget to change the global pop-up menu while you’re browsing your calendar), your iCal will be a confusing mish-mash of appointments that are scattered all over the place!

This sort of confusing mess might be acceptable for people who actually want to go through this, but what about the vast majority of people who don’t want to use this feature at all? What about the normal person who just wants his lunch appointment to stay at noon?

We’ve already established that iCal’s behavior does NOT change whether time zone support is turned on or off, so sadly, the only real workaround for this is to turn ON time zone support and then manually remember to set every one of your appointments to a “floating time zone”, which is one of your time zone choices in iCal. A “floating time zone” means that your appointment time stays the same no matter which time zone you’re traveling in.

Now doesn’t this sound great? Wouldn’t it be great if all of your appointment times stayed the same on your calendar at all times? If you’re one of the 98% of people who just want your appointments to always stay “as is” on your calendar, then wouldn’t you want EVERY event to always be assigned to a floating time zone?

Yes, of course! Let’s make every event a floating event by default!

Unfortunately, Apple provides absolutely no way to make every single one of your events default to a floating event. Even if you completely turn off time zone support in iCal, it will still tag all of your new appointments with an actual time zone, unbeknownst to you.

There is no easy way for you, the user, to automatically change all of your appointments to a “floating time zone”. You have to manually and painstakingly go through every single appointment – past, present, and future — and change it to a “floating time zone”.

So what we really need is for Apple to step in here and put an end to this madness.

The simple solution that Apple needs to implement is this: iCal appointments should always auto-select the “floating time zone” when time zone support is turned off. In other words, if the user hasn’t specifically chosen to turn on time zone support, then every event — by default — should be a floating event. That’s the solution that we really need, but it has to come from Apple.

If you feel the same way as me about this issue, please be sure to send your feedback to Apple at

4 Comments leave one →
  1. December 2, 2010 10:47 AM

    Wow! I can’t believe that no one has responded to this. You are so right on this issue. I have lived with this problem since 2003, first on a Windows PC, and now on a Mac. These people must never leave Pacific Standard Time! Since 2003, I have lived in Indiana, French Polynesia, Fiji and Vanuatu, not to mention other countries and time zones that I have visited. I have had to turn off the “Set time and date automatically” feature and leave my computers set for Indiana time. Of course, that might mean that the date stamping of emails and possibly other items is off by hours. So far, that is the only solution that I know of. If you’ve come up with another one, please let me know.

  2. February 25, 2015 3:30 PM

    I believe OS X 10.10 has either changed default behavior or something else different. There’s no longer any option to make things ‘floating,’ so I believe that is the default for any new and existing events when Time Zone Support (which IS still on option) is switched OFF. I’m about to find out (traveling from Boston to LA this weekend).

  3. February 25, 2015 11:43 PM

    I would recommend checking out BusyCal. It is a superior calendar app for the Mac, plus it includes a “Floating” option when Time Zone Support is turned on, and you’ve chosen to show the Time Zone field in the Info Panel preferences. Note that BusyCal won’t let you set Floating as the DEFAULT time zone, but it is always available as a drop-down selection for each event.

  4. August 19, 2016 5:42 AM

    I applaud your perfect description of both problem and solution. I made a feature request with Apple, and copied your exact wording in the last paragraph. I became aware of this “feature” when I moved from NY to CA – I’d never used time zones before, and yet suddenly, all my appointments were off by three hours! I had a long conversation with Apple, but never until I read your post had I heard the term “floating time zone”… grrr! Thank you!

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