FAQ: What the daylight saving shift means to you

Editor's note: This FAQ was originally published last spring. It's been updated to account for the fall changing of the clocks.

faq The fact that the U.S. is "falling back" a week late has left some folks with a few headaches, along with an unwarranted extra hour of sleep.

Standard time, which ordinarily would have kicked in at 2 a.m. Sunday, won't take place until next Sunday. Congress is to thank (or blame) for the change, which also meant daylight saving time started two weeks early. The thing is, computers weren't programmed with legislative intent in mind. Many gadget and software makers have issued patches to adjust to the change, though not everyone has installed the changes, and even people whose systems are now patched could see some calendar items showing up an hour off.

Here's a list of some commonly asked questions and answers regarding the time shift.

Q: So, daylight saving time is lasting an extra week. What's the big deal?
Most computers these days are set to automatically move forward each year to daylight saving and then back an hour in the fall. That's important, particularly for time-sensitive programs like calendars. Without a software update--and even with one in some cases--calendar items may be off by an hour.

So what do I need to do?
Microsoft released an update to Windows in November that prompts Windows to make the move. The company also has other patches available on its Web site. The patch was delivered in February to Windows XP Service Pack 2 users who have automatic updates turned on, but others may need to download the patch or manually adjust their PC's clock. Apple issued an update for Mac OS X Tiger in February 2006 and offered an updated patch last month for users of Tiger as well as Mac OS X 10.3 Panther.

Are all my calendar items going to be off by an hour?
No. Only calendar items during the extra daylight saving time (the additional three weeks of March and the last week of October) will be affected. Depending on how your business is managing things, many of your one-time calendar items might already be fixed, but it is worth taking a look at your calendar and double-checking the time for any crucial meetings.

Are there any precautions that I should take?
It's a good idea to start taking a look at your calendar for the next few weeks. Double-check when key appointments are supposed to be and note that in the text of the calendar item. That way, even if the time gets moved an hour off, you still know what time that appointment is supposed to be.

Is it just calendars that could be affected?
No. The move could impact time-sensitive applications other than calendaring, such as those that process sales orders or keep track of time cards. Gartner, for example, says the bug could lead to incorrect arrival and departure times in the travel industry and result in errors in bank transactions. In addition, trading applications might execute purchases and sales at the wrong time, and cell phone-billing software could charge peak rates at off-peak hours. Manufacturing operations that are computer-automated could also suffer.

What about my cell phone?
An update is available for Windows Mobile-based cell phones as well as Palm OS devices. Most standard cell phones set their clock based on the network time, so they should adjust automatically.

Are there other places around the world that are also making the early switch?
Yes. Canada is also changing its shift from daylight saving time, at least for the regions that observe daylight saving time, as are Western Australia, central Brazil and Tehran, Iran.