This issue is important if you live in the United States and have a Windows PC. Because of recent rule changes, Daylight Saving Time was extended starting in 2007, and unless you make some changes, your system's clock will not be accurate. Unlike other problems that become a big deal when Microsoft does this or that, when this or that product is updated or discontinued, etc, this issue has a very specific time at which it will bite you. At 2:00 AM local time on Sunday March 11, 2007, your system's clock will be one hour slow. This will continue for three weeks, until the old rules call for Daylight Saving Time to take effect, on Sunday April 1, 2007, at 2:00 AM. At that time, everything will be back to normal, and you will have an accurate clock once again. The problem will resurface at 2:00 AM on Sunday October 28, 2007, when the old rule has Daylight Saving Time end, and last for one week, during which time your system clock will be one hour fast. There will be similar periods of inaccuracy in future years. This document describes a way to fix this problem by editing your Windows timezone data to reflect the new changes. Windows Vista has these changes installed already from the factory, so you don't need to worry about this if you're running Vista. In addition, there is an update for supported Windows operating systems to make these changes, but this method can be used if you don't want to bother with that. This method also works on operating systems that are no longer being supported by Microsoft, such as Windows 95/98/98SE.

To do this, you first need to download the timezone editor program here. Unzip the file into your windows directory.

Trouble unzipping the file? Try downloading the file tzsetup.exe and running it. The necessary files will be automatically installed into your c:\windows directory.

Now you need to run the tzedit.exe program from the Start, Run dialog. A window will pop up. You will be in a list of the available timezones, with your current timezone already selected. If you live in the United States, you will almost definitely want to edit this timezone, so tab to the "Edit" button and click it. A new dialog will come up. Tab over to the Daylight Saving Time section, and change the combo boxes for the days. Currently, the "Start Day" boxes will read "First Sunday of April," and you want to change them to "Second Sunday of March." Likewise, for the "Last Day" combo boxes, change them from "Last Sunday in October" to "First Sunday in November." These are standard combo boxes, so arrowing through them will make all of this self-explanatory. Don't change the time edit boxes or anything else. Click "OK" to save your changes. Now Shift+Tab over to the list of timezones and arrow until you get to another timezone you want to edit. For completeness, I always edit all of the US timezones. These include "(GMT-05:00) Eastern (US and Canada)," "(GMT-06:00) Central (US and Canada)," "(GMT-07:00) Mountain (US and Canada)," "(GMT-08:00) Pacific (US and Canada); Tijuana," and "(GMT-09:00) Alaska." You don't need to edit "(GMT- 10:00) Hawaii," because Hawaii does not observe Daylight Saving Time. If you live in some parts of Mexico that use US Pacific Time, the Daylight Saving Time dates have not changed. To deal with this, you will need to create a new timezone, set the GMT Offset to - 08:00 and use the old Daylight Saving Time dates described above. When you're all done, click the "Close" button to exit the program.

Once you've edited your timezones, you need to go into your system's Control Panel, and select the Date/Time option. On Windows 98SE, the Timezone selection is on the Date/Time tab, while on XP, there is a separate Timezone tab. In any event, find the timezone selector, and arrow up once then down once to reselect the current timezone, then hit Enter, and exit the Control Panel. At this point your system should be ready to deal with the new Daylight Saving Time rules.

If you have any questions about this process, please don't hesitate to E-mail me.